Lay down the foundation for packaging the .NET echosystem

- fetchNuGet can fetch binaries from nuget servers
- buildDotnetPackage can build .NET packages using mono/xbuild
  - Places nuget & paket as they would clash with nix
  - Patch project files because F# targets are expected to be found in
    the mono directory (and we know that's not going to happen on nix)
  - Find DLLs that were copied from buildInputs and replace by symlink
    for sharing
  - Export produced DLL via the pkg-config mechanism
  - Create wrappers for produced EXEs
- Repackaged this new infrastructure: keepass, monodevelop
- Newly packaged: ExtCore, UnionArgParser, FSharp.Data, Paket, and a
  bunch more..

This is a combination of 73 commits.

20 files changed, 1159 insertions, 76 deletions

diff --git a/pkgs/applications/editors/monodevelop/default.nix b/pkgs/applications/editors/monodevelop/default.nix
index b04e37746e05..b27bc75ed59e 100644
--- a/pkgs/applications/editors/monodevelop/default.nix
+++ b/pkgs/applications/editors/monodevelop/default.nix
@@ -1,6 +1,7 @@
-{ stdenv, fetchurl, fetchgit
+{ stdenv, fetchurl, fetchgit, fetchNuGet
 , autoconf, automake, pkgconfig, shared_mime_info, intltool
 , glib, mono, gtk-sharp, gnome, gnome-sharp, unzip
+, dotnetPackages
 }:
 
 stdenv.mkDerivation rec {
@@ -13,79 +14,33 @@ stdenv.mkDerivation rec {
     sha256 = "1bgqvlfi6pilj2zxsviqilh63qq98wsijqdiqwpkqchcw741zlyn";
   };
 
-  srcNugetBinary = fetchgit {
-    url = "https://github.com/mono/nuget-binary.git";
-    rev = "da1f2102f8172df6f7a1370a4998e3f88b91c047";
-    sha256 = "1hbnckc4gvqkknf8gh1k7iwqb4vdzifdjd19i60fnczly5v8m1c3";
-  };
-
-  srcNUnit = fetchurl {
-    url = "https://www.nuget.org/api/v2/package/NUnit/2.6.3";
-    sha256 = "0bb16i4ggwz32wkxsh485wf014cqqzhbyx0b3wbpmqjw7p4canph";
-  };
-
-  srcNUnitRunners = fetchurl {
-    url = "https://www.nuget.org/api/v2/package/NUnit.Runners/2.6.3";
-    sha256 = "0qwx1i9lxkp9pijj2bsczzgsamz651hngkxraqjap1v4m7d09a3b";
-  };
-
-  srcNUnit2510 = fetchurl {
+  nunit2510 = fetchurl {
     url = "http://launchpad.net/nunitv2/2.5/2.5.10/+download/NUnit-2.5.10.11092.zip";
     sha256 = "0k5h5bz1p2v3d0w0hpkpbpvdkcszgp8sr9ik498r1bs72w5qlwnc";
   };
 
-  srcNugetSystemWebMvcExtensions = fetchurl {
-    url = https://www.nuget.org/api/v2/package/System.Web.Mvc.Extensions.Mvc.4/1.0.9;
-    sha256 = "19wi662m8primpimzifv8k560m6ymm73z0mf1r8ixl0xqag1hx6j";
-  };
-
-  srcNugetMicrosoftAspNetMvc = fetchurl {
-    url = https://www.nuget.org/api/v2/package/Microsoft.AspNet.Mvc/5.2.2;
-    sha256 = "1jwfmz42kw2yb1g2hgp2h34fc4wx6s8z71da3mw5i4ivs25w9n2b";
-  };
-
-  srcNugetMicrosoftAspNetRazor = fetchurl {
-    url = https://www.nuget.org/api/v2/package/Microsoft.AspNet.Razor/3.2.2;
-    sha256 = "1db3apn4vzz1bx6q5fyv6nyx0drz095xgazqbw60qnhfs7z45axd";
-  };
-
-  srcNugetMicrosoftAspNetWebPages = fetchurl {
-    url = https://www.nuget.org/api/v2/package/Microsoft.AspNet.WebPages/3.2.2;
-    sha256 = "17fwb5yj165sql80i47zirjnm0gr4n8ypz408mz7p8a1n40r4i5l";
-  };
-
-  srcNugetMicrosoftWebInfrastructure = fetchurl {
-    url = https://www.nuget.org/api/v2/package/Microsoft.Web.Infrastructure/1.0.0.0;
-    sha256 = "1mxl9dri5729d0jl84gkpqifqf4xzb6aw1rzcfh6l0r24bix9afn";
-  };
-
   postPatch = ''
     # From https://bugzilla.xamarin.com/show_bug.cgi?id=23696#c19
 
-    # it seems parts of MonoDevelop 5.2+ need NUnit 2.6.4, which isn't included
-    # (?), so download it and put it in the right place in the tree
-    mkdir packages
-    unzip ${srcNUnit} -d packages/NUnit.2.6.3
-    unzip ${srcNUnitRunners} -d packages/NUnit.Runners.2.6.3
-
     # cecil needs NUnit 2.5.10 - this is also missing from the tar
-    unzip -j ${srcNUnit2510} -d external/cecil/Test/libs/nunit-2.5.10 NUnit-2.5.10.11092/bin/net-2.0/framework/\*
+    unzip -j ${nunit2510} -d external/cecil/Test/libs/nunit-2.5.10 NUnit-2.5.10.11092/bin/net-2.0/framework/\*
 
     # the tar doesn't include the nuget binary, so grab it from github and copy it
     # into the right place
-    cp -vfR ${srcNugetBinary}/* external/nuget-binary/
-
-    # AspNet plugin requires these packages
-    unzip ${srcNugetSystemWebMvcExtensions} -d packages/System.Web.Mvc.Extensions.Mvc.4.1.0.9
-    unzip ${srcNugetMicrosoftAspNetMvc} -d packages/Microsoft.AspNet.Mvc.5.2.2
-    unzip ${srcNugetMicrosoftAspNetRazor} -d packages/Microsoft.AspNet.Razor.3.2.2
-    unzip ${srcNugetMicrosoftAspNetWebPages} -d packages/Microsoft.AspNet.WebPages.3.2.2
-    unzip ${srcNugetMicrosoftWebInfrastructure} -d packages/Microsoft.Web.Infrastructure.1.0.0.0
+    cp -vfR "$(dirname $(pkg-config NuGet.Core --variable=Libraries))"/* external/nuget-binary/
   '';
 
+  # Revert this commit which broke the ability to use pkg-config to locate dlls
+  patchFlags = [ "-p2" ];
+  patches = [ ./git-revert-12d610fb3f6dce121df538e36f21d8c2eeb0a6e3.patch ];
+
   buildInputs = [
     autoconf automake pkgconfig shared_mime_info intltool
     mono gtk-sharp gnome-sharp unzip
+    pkgconfig
+    dotnetPackages.NUnit
+    dotnetPackages.NUnitRunners
+    dotnetPackages.Nuget
   ];
 
   preConfigure = "patchShebangs ./configure";
@@ -108,6 +63,12 @@ stdenv.mkDerivation rec {
     > 
     EOF
     done
+
+    # Without this, you get a missing DLL error any time you install an addin..
+    ln -sv `pkg-config nunit.core --variable=Libraries` $out/lib/monodevelop/AddIns/NUnit
+    ln -sv `pkg-config nunit.core.interfaces --variable=Libraries` $out/lib/monodevelop/AddIns/NUnit
+    ln -sv `pkg-config nunit.framework --variable=Libraries` $out/lib/monodevelop/AddIns/NUnit
+    ln -sv `pkg-config nunit.util --variable=Libraries` $out/lib/monodevelop/AddIns/NUnit
   '';
 
   dontStrip = true;
diff --git a/pkgs/applications/editors/monodevelop/git-revert-12d610fb3f6dce121df538e36f21d8c2eeb0a6e3.patch b/pkgs/applications/editors/monodevelop/git-revert-12d610fb3f6dce121df538e36f21d8c2eeb0a6e3.patch
new file mode 100644
index 000000000000..969aad33ec0b
--- /dev/null
+++ b/pkgs/applications/editors/monodevelop/git-revert-12d610fb3f6dce121df538e36f21d8c2eeb0a6e3.patch
@@ -0,0 +1,57 @@
+diff --git a/main/src/addins/AspNet/MonoDevelop.AspNet.csproj b/main/src/addins/AspNet/MonoDevelop.AspNet.csproj
+index 02d3a01..c6daaad 100644
+--- a/main/src/addins/AspNet/MonoDevelop.AspNet.csproj
++++ b/main/src/addins/AspNet/MonoDevelop.AspNet.csproj
+@@ -452,34 +452,6 @@
+     <None Include="Templates\Projects\WebApplication.xpt.xml">
+       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+     </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.Mvc.5.2.2\lib\net45\System.Web.Mvc.dll">
+-      <Link>System.Web.Mvc.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.Razor.3.2.2\lib\net45\System.Web.Razor.dll">
+-      <Link>System.Web.Razor.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.WebPages.3.2.2\lib\net45\System.Web.Helpers.dll">
+-      <Link>System.Web.Helpers.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.WebPages.3.2.2\lib\net45\System.Web.WebPages.Deployment.dll">
+-      <Link>System.Web.WebPages.Deployment.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.WebPages.3.2.2\lib\net45\System.Web.WebPages.dll">
+-      <Link>System.Web.WebPages.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.AspNet.WebPages.3.2.2\lib\net45\System.Web.WebPages.Razor.dll">
+-      <Link>System.Web.WebPages.Razor.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+-    <None Include="..\..\..\packages\Microsoft.Web.Infrastructure.1.0.0.0\lib\net40\Microsoft.Web.Infrastructure.dll">
+-      <Link>Microsoft.Web.Infrastructure.dll</Link>
+-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+-    </None>
+     <None Include="packages.config" />
+   </ItemGroup>
+   <ItemGroup>
+diff --git a/main/src/addins/AspNet/Properties/MonoDevelop.AspNet.addin.xml b/main/src/addins/AspNet/Properties/MonoDevelop.AspNet.addin.xml
+index eab7c32..4a75311 100644
+--- a/main/src/addins/AspNet/Properties/MonoDevelop.AspNet.addin.xml
++++ b/main/src/addins/AspNet/Properties/MonoDevelop.AspNet.addin.xml
+@@ -1,13 +1,6 @@
+ <ExtensionModel>

+ 	

+ 	<Runtime>

+-		<Import assembly = "System.Web.Helpers.dll" />
+-		<Import assembly = "System.Web.Mvc.dll" />
+-		<Import assembly = "System.Web.Razor.dll" />
+-		<Import assembly = "System.Web.WebPages.Deployment.dll" />
+-		<Import assembly = "System.Web.WebPages.dll" />
+-		<Import assembly = "System.Web.WebPages.Razor.dll" />
+-
+ 		<Import file = "Html/Schemas/xhtml1-strict.xsd" />

+ 		<Import file = "Html/Schemas/xhtml1-transitional.xsd" />

+ 		<Import file = "Html/Schemas/xhtml1-frameset.xsd" />

diff --git a/pkgs/applications/misc/keepass/default.nix b/pkgs/applications/misc/keepass/default.nix
index d46efc4e5e89..f659e4f6c2dd 100644
--- a/pkgs/applications/misc/keepass/default.nix
+++ b/pkgs/applications/misc/keepass/default.nix
@@ -1,17 +1,21 @@
-{ stdenv, fetchurl, unzip, makeDesktopItem, mono }:
+{ stdenv, fetchurl, buildDotnetPackage, makeWrapper, unzip, makeDesktopItem }:
 
-stdenv.mkDerivation rec {
-  name = "keepass-${version}";
+buildDotnetPackage rec {
+  baseName = "keepass";
   version = "2.29";
 
   src = fetchurl {
-    url = "mirror://sourceforge/keepass/KeePass-${version}.zip";
-    sha256 = "16x7m899akpi036c0wlr41w7fz9q0b69yac9q97rqkixb03l4g9d";
+    url = "mirror://sourceforge/keepass/KeePass-${version}-Source.zip";
+    sha256 = "051s0aznyyhbpdbly6h5rs0ax0zvkp45dh93nmq6lwhicswjwn5m";
   };
 
   sourceRoot = ".";
 
-  phases = [ "unpackPhase" "installPhase" ];
+  buildInputs = [ unzip ];
+
+  patches = [ ./keepass.patch ];
+
+  preConfigure = "rm -rvf Build/*";
 
   desktopItem = makeDesktopItem {
     name = "keepass";
@@ -22,23 +26,19 @@ stdenv.mkDerivation rec {
     categories = "Application;Other;";
   };
 
+  outputFiles = [ "Build/KeePass/Release/*" "Build/KeePassLib/Release/*" ];
+  dllFiles = [ "KeePassLib.dll" ];
+  exeFiles = [ "KeePass.exe" ];
 
-  installPhase = ''
-    mkdir -p "$out/bin"
-    echo "${mono}/bin/mono $out/KeePass.exe" > $out/bin/keepass
-    chmod +x $out/bin/keepass
-    echo $out
-    cp -r ./* $out/
+  postInstall = ''
     mkdir -p "$out/share/applications"
     cp ${desktopItem}/share/applications/* $out/share/applications
   '';
 
-  buildInputs = [ unzip ];
-
   meta = {
     description = "GUI password manager with strong cryptography";
     homepage = http://www.keepass.info/;
-    maintainers = with stdenv.lib.maintainers; [amorsillo];
+    maintainers = with stdenv.lib.maintainers; [ amorsillo obadz ];
     platforms = with stdenv.lib.platforms; all;
     license = stdenv.lib.licenses.gpl2;
   };
diff --git a/pkgs/applications/misc/keepass/keepass.patch b/pkgs/applications/misc/keepass/keepass.patch
new file mode 100644
index 000000000000..6ecf0bb074de
--- /dev/null
+++ b/pkgs/applications/misc/keepass/keepass.patch
@@ -0,0 +1,89 @@
+diff -Naur old/KeePass/KeePass.csproj new/KeePass/KeePass.csproj
+--- old/KeePass/KeePass.csproj	2015-04-10 11:00:46.000000000 +0100
++++ new/KeePass/KeePass.csproj	2015-05-27 16:35:52.196177593 +0100
+@@ -1,4 +1,4 @@
+-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">

++<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">

+   <PropertyGroup>

+     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>

+     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>

+@@ -10,7 +10,7 @@
+     <RootNamespace>KeePass</RootNamespace>

+     <AssemblyName>KeePass</AssemblyName>

+     <ApplicationIcon>KeePass.ico</ApplicationIcon>

+-    <SignAssembly>true</SignAssembly>

++    <SignAssembly>false</SignAssembly>

+     <AssemblyOriginatorKeyFile>KeePass.pfx</AssemblyOriginatorKeyFile>

+     <FileUpgradeFlags>

+     </FileUpgradeFlags>

+@@ -1316,6 +1316,5 @@
+   </Target>

+   -->

+   <PropertyGroup>

+-    <PostBuildEvent>"$(FrameworkSDKDir)bin\sgen.exe" /assembly:"$(TargetPath)" /force /nologo /compiler:/keycontainer:VS_KEY_33430356D8D7D1B8 /compiler:/delaysign-</PostBuildEvent>

+   </PropertyGroup>

+-</Project>
+\ No newline at end of file
++</Project>

+diff -Naur old/KeePassLib/KeePassLib.csproj new/KeePassLib/KeePassLib.csproj
+--- old/KeePassLib/KeePassLib.csproj	2014-05-08 15:00:24.000000000 +0100
++++ new/KeePassLib/KeePassLib.csproj	2015-05-27 16:35:52.197177562 +0100
+@@ -1,4 +1,4 @@
+-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">

++<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">

+   <PropertyGroup>

+     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>

+     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>

+@@ -9,7 +9,7 @@
+     <AppDesignerFolder>Properties</AppDesignerFolder>

+     <RootNamespace>KeePassLib</RootNamespace>

+     <AssemblyName>KeePassLib</AssemblyName>

+-    <SignAssembly>true</SignAssembly>

++    <SignAssembly>false</SignAssembly>

+     <AssemblyOriginatorKeyFile>KeePassLib.pfx</AssemblyOriginatorKeyFile>

+     <FileUpgradeFlags>

+     </FileUpgradeFlags>

+diff -Naur old/KeePass.sln new/KeePass.sln
+--- old/KeePass.sln	2009-08-31 19:47:28.000000000 +0100
++++ new/KeePass.sln	2015-05-27 16:35:59.568953518 +0100
+@@ -1,11 +1,9 @@
+-Microsoft Visual Studio Solution File, Format Version 10.00

++Microsoft Visual Studio Solution File, Format Version 12.00

+ # Visual Studio 2008

+ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KeePassLib", "KeePassLib\KeePassLib.csproj", "{53573E4E-33CB-4FDB-8698-C95F5E40E7F3}"

+ EndProject

+ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KeePass", "KeePass\KeePass.csproj", "{10938016-DEE2-4A25-9A5A-8FD3444379CA}"

+ EndProject

+-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KeePassLibSD", "KeePassLibSD\KeePassLibSD.csproj", "{DC15F71A-2117-4DEF-8C10-AA355B5E5979}"

+-EndProject

+ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TrlUtil", "Translation\TrlUtil\TrlUtil.csproj", "{B7E890E7-BF50-4450-9A52-C105BD98651C}"

+ EndProject

+ Global

+@@ -44,18 +42,6 @@
+ 		{10938016-DEE2-4A25-9A5A-8FD3444379CA}.Release|Mixed Platforms.Build.0 = Release|Any CPU

+ 		{10938016-DEE2-4A25-9A5A-8FD3444379CA}.Release|Win32.ActiveCfg = Release|Any CPU

+ 		{10938016-DEE2-4A25-9A5A-8FD3444379CA}.Release|x64.ActiveCfg = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|Any CPU.Build.0 = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|Win32.ActiveCfg = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Debug|x64.ActiveCfg = Debug|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|Any CPU.ActiveCfg = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|Any CPU.Build.0 = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|Mixed Platforms.Build.0 = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|Win32.ActiveCfg = Release|Any CPU

+-		{DC15F71A-2117-4DEF-8C10-AA355B5E5979}.Release|x64.ActiveCfg = Release|Any CPU

+ 		{B7E890E7-BF50-4450-9A52-C105BD98651C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+ 		{B7E890E7-BF50-4450-9A52-C105BD98651C}.Debug|Any CPU.Build.0 = Debug|Any CPU

+ 		{B7E890E7-BF50-4450-9A52-C105BD98651C}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU

+diff -Naur old/Translation/TrlUtil/TrlUtil.csproj new/Translation/TrlUtil/TrlUtil.csproj
+--- old/Translation/TrlUtil/TrlUtil.csproj	2013-07-21 10:06:38.000000000 +0100
++++ new/Translation/TrlUtil/TrlUtil.csproj	2015-05-27 16:35:52.197177562 +0100
+@@ -1,4 +1,4 @@
+-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">

++<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">

+   <PropertyGroup>

+     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>

+     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>

diff --git a/pkgs/build-support/build-dotnet-package/default.nix b/pkgs/build-support/build-dotnet-package/default.nix
new file mode 100644
index 000000000000..00be987af752
--- /dev/null
+++ b/pkgs/build-support/build-dotnet-package/default.nix
@@ -0,0 +1,109 @@
+{ stdenv, lib, makeWrapper, pkgconfig, mono, dotnetbuildhelpers }:
+
+attrsOrig @
+{ baseName
+, version
+, buildInputs ? []
+, xBuildFiles ? [ ]
+, xBuildFlags ? [ "/p:Configuration=Release" ]
+, outputFiles ? [ "bin/Release/*" ]
+, dllFiles ? [ "*.dll" ]
+, exeFiles ? [ "*.exe" ]
+, ... }:
+  let
+    arrayToShell = (a: toString (map (lib.escape (lib.stringToCharacters "\\ ';$`()|<>\t") ) a));
+
+    attrs = {
+      name = "${baseName}-${version}";
+
+      buildInputs = [
+        pkgconfig
+        mono
+        dotnetbuildhelpers
+        makeWrapper
+      ] ++ buildInputs;
+
+      configurePhase = ''
+        runHook preConfigure
+
+        [ -z "$dontPlacateNuget" ] && placate-nuget.sh
+        [ -z "$dontPlacatePaket" ] && placate-paket.sh
+        [ -z "$dontPatchFSharpTargets" ] && patch-fsharp-targets.sh
+
+        runHook postConfigure
+      '';
+
+      buildPhase = ''
+        runHook preBuild
+
+        echo Building dotNET packages...
+
+        # Probably needs to be moved to fsharp
+        if pkg-config FSharp.Core
+        then
+          export FSharpTargetsPath="$(dirname $(pkg-config FSharp.Core --variable=Libraries))/Microsoft.FSharp.Targets"
+        fi
+
+        ran=""
+        for xBuildFile in ${arrayToShell xBuildFiles} ''${xBuildFilesExtra}
+        do
+          ran="yes"
+          xbuild ${arrayToShell xBuildFlags} ''${xBuildFlagsArray} $xBuildFile
+        done
+
+        [ -z "$ran" ] && xbuild ${arrayToShell xBuildFlags} ''${xBuildFlagsArray}
+
+        runHook postBuild
+      '';
+
+      dontStrip = true;
+
+      installPhase = ''
+        runHook preInstall
+
+        target="$out/lib/dotnet/${baseName}"
+        mkdir -p "$target"
+
+        cp -rv ${arrayToShell outputFiles} "''${outputFilesArray[@]}" "$target"
+
+        if [ -z "$dontRemoveDuplicatedDlls" ]
+        then
+          pushd "$out"
+          remove-duplicated-dlls.sh
+          popd
+        fi
+
+        set -f
+        for dllPattern in ${arrayToShell dllFiles} ''${dllFilesArray[@]}
+        do
+          set +f
+          for dll in "$target"/$dllPattern
+          do
+            [ -f "$dll" ] || continue
+            if pkg-config $(basename -s .dll "$dll")
+            then
+              echo "$dll already exported by a buildInputs, not re-exporting"
+            else
+              ${dotnetbuildhelpers}/bin/create-pkg-config-for-dll.sh "$out/lib/pkgconfig" "$dll"
+            fi
+          done
+        done
+
+        set -f
+        for exePattern in ${arrayToShell exeFiles} ''${exeFilesArray[@]}
+        do
+          set +f
+          for exe in "$target"/$exePattern
+          do
+            [ -f "$exe" ] || continue
+            mkdir -p "$out"/bin
+            commandName="$(basename -s .exe "$(echo "$exe" | tr "[A-Z]" "[a-z]")")"
+            makeWrapper "${mono}/bin/mono \"$exe\"" "$out"/bin/"$commandName"
+          done
+        done
+
+        runHook postInstall
+      '';
+    };
+  in
+    stdenv.mkDerivation (attrs // (builtins.removeAttrs attrsOrig [ "buildInputs" ] ))
diff --git a/pkgs/build-support/dotnetbuildhelpers/create-pkg-config-for-dll.sh b/pkgs/build-support/dotnetbuildhelpers/create-pkg-config-for-dll.sh
new file mode 100644
index 000000000000..379141704523
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/create-pkg-config-for-dll.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+targetDir="$1"
+dllFullPath="$2"
+
+dllVersion="$(monodis --assembly "$dllFullPath" | grep ^Version: | cut -f 2 -d : | xargs)"
+[ -z "$dllVersion" ] && echo "Defaulting dllVersion to 0.0.0" && dllVersion="0.0.0"
+dllFileName="$(basename $dllFullPath)"
+dllRootName="$(basename -s .dll $dllFileName)"
+targetPcFile="$targetDir"/"$dllRootName".pc
+
+mkdir -p "$targetDir"
+
+cat > $targetPcFile << EOF
+Libraries=$dllFullPath
+
+Name: $dllRootName
+Description: $dllRootName
+Version: $dllVersion
+Libs: -r:$dllFileName
+EOF
+
+echo "Created $targetPcFile"
diff --git a/pkgs/build-support/dotnetbuildhelpers/default.nix b/pkgs/build-support/dotnetbuildhelpers/default.nix
new file mode 100644
index 000000000000..ed0d4f790c81
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/default.nix
@@ -0,0 +1,18 @@
+{ helperFunctions, mono, pkgconfig }:
+  helperFunctions.runCommand
+    "dotnetbuildhelpers"
+    { preferLocalBuild = true; }
+    ''
+      target="$out/bin"
+      mkdir -p "$target"
+
+      for script in ${./create-pkg-config-for-dll.sh} ${./patch-fsharp-targets.sh} ${./remove-duplicated-dlls.sh} ${./placate-nuget.sh} ${./placate-paket.sh}
+      do
+        scriptName="$(basename "$script" | cut -f 2- -d -)"
+        cp -v "$script" "$target"/"$scriptName"
+        chmod 755 "$target"/"$scriptName"
+        patchShebangs "$target"/"$scriptName"
+        substituteInPlace "$target"/"$scriptName" --replace pkg-config ${pkgconfig}/bin/pkg-config
+        substituteInPlace "$target"/"$scriptName" --replace monodis ${mono}/bin/monodis
+      done
+    ''
diff --git a/pkgs/build-support/dotnetbuildhelpers/patch-fsharp-targets.sh b/pkgs/build-support/dotnetbuildhelpers/patch-fsharp-targets.sh
new file mode 100644
index 000000000000..3f81cc73e801
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/patch-fsharp-targets.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+# Some project files look for F# targets in $(FSharpTargetsPath)
+# so it's a good idea to add something like this to your ~/.bash_profile:
+
+# export FSharpTargetsPath=$(dirname $(which fsharpc))/../lib/mono/4.0/Microsoft.FSharp.Targets
+
+# In build scripts, you would add somehting like this:
+
+# export FSharpTargetsPath="${fsharp}/lib/mono/4.0/Microsoft.FSharp.Targets"
+
+# However, some project files look for F# targets in the main Mono directory. When that happens
+# patch the project files using this script so they will look in $(FSharpTargetsPath) instead.
+
+echo "Patching F# targets in fsproj files..."
+
+find -iname \*.fsproj -print -exec \
+  sed --in-place=.bak \
+    -e 's,<FSharpTargetsPath>\([^<]*\)</FSharpTargetsPath>,<FSharpTargetsPath Condition="Exists('\'\\1\'')">\1</FSharpTargetsPath>,'g \
+    {} \;
diff --git a/pkgs/build-support/dotnetbuildhelpers/placate-nuget.sh b/pkgs/build-support/dotnetbuildhelpers/placate-nuget.sh
new file mode 100644
index 000000000000..8a7f36522a3d
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/placate-nuget.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+echo Placating Nuget in nuget.targets
+find -iname nuget.targets -print -exec sed --in-place=bak -e 's,mono --runtime[^<]*,true NUGET PLACATED BY buildDotnetPackage,g' {} \;
+
+echo Just to be sure, replacing Nuget executables by empty files.
+find . -iname nuget.exe \! -size 0 -exec mv -v {} {}.bak \; -exec touch {} \;
diff --git a/pkgs/build-support/dotnetbuildhelpers/placate-paket.sh b/pkgs/build-support/dotnetbuildhelpers/placate-paket.sh
new file mode 100644
index 000000000000..0dbf1eecbad8
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/placate-paket.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+echo Placating Paket in paket.targets
+find -iname paket.targets -print -exec sed --in-place=bak -e 's,mono --runtime[^<]*,true PAKET PLACATED BY buildDotnetPackage,g' {} \;
+
+echo Just to be sure, replacing Paket executables by empty files.
+find . -iname paket\*.exe \! -size 0 -exec mv -v {} {}.bak \; -exec touch {} \;
diff --git a/pkgs/build-support/dotnetbuildhelpers/remove-duplicated-dlls.sh b/pkgs/build-support/dotnetbuildhelpers/remove-duplicated-dlls.sh
new file mode 100644
index 000000000000..d8d29912c8fa
--- /dev/null
+++ b/pkgs/build-support/dotnetbuildhelpers/remove-duplicated-dlls.sh
@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+IFS="
+"
+
+for dll in $(find -iname \*.dll)
+do
+    baseName="$(basename "$dll" | sed "s/.dll$//i")"
+    if pkg-config "$baseName"
+    then
+        candidateDll="$(pkg-config "$baseName" --variable=Libraries)"
+
+        if diff "$dll" "$candidateDll" >/dev/null
+        then
+            echo "$dll is identical to $candidateDll. Substituting..."
+            rm -vf "$dll"
+            ln -sv "$candidateDll" "$dll"
+        else
+            echo "$dll and $candidateDll share the same name but have different contents, leaving alone."
+        fi
+    fi
+done
diff --git a/pkgs/build-support/fetchnuget/default.nix b/pkgs/build-support/fetchnuget/default.nix
new file mode 100644
index 000000000000..803db27c9d56
--- /dev/null
+++ b/pkgs/build-support/fetchnuget/default.nix
@@ -0,0 +1,40 @@
+{ stdenv, fetchurl, buildDotnetPackage, unzip }:
+
+attrs @
+{ baseName
+, version
+, url ? "https://www.nuget.org/api/v2/package/${baseName}/${version}"
+, sha256 ? ""
+, md5 ? ""
+, ...
+}:
+  buildDotnetPackage ({
+    src = fetchurl {
+      inherit url sha256 md5;
+      name = "${baseName}.${version}.zip";
+    };
+
+    sourceRoot = ".";
+
+    buildInputs = [ unzip ];
+
+    phases = [ "unpackPhase" "installPhase" ];
+
+    preInstall = ''
+      function traverseRename () {
+        for e in *
+        do
+          t="$(echo "$e" | sed -e "s/%20/\ /g" -e "s/%2B/+/g")"
+          [ "$t" != "$e" ] && mv -vn "$e" "$t"
+          if [ -d "$t" ]
+          then
+            cd "$t"
+            traverseRename
+            cd ..
+          fi
+        done
+      }
+
+      traverseRename
+   '';
+  } // attrs)
diff --git a/pkgs/development/compilers/fsharp/default.nix b/pkgs/development/compilers/fsharp/default.nix
index 82742cf9af69..92d80deb532e 100644
--- a/pkgs/development/compilers/fsharp/default.nix
+++ b/pkgs/development/compilers/fsharp/default.nix
@@ -1,4 +1,6 @@
-{ stdenv, fetchurl, mono, pkgconfig, autoconf, automake, which }:
+# Temporaririly avoid dependency on dotnetbuildhelpers to avoid rebuilding many times while working on it
+
+{ stdenv, fetchurl, mono, pkgconfig, dotnetbuildhelpers, autoconf, automake, which }:
 
 stdenv.mkDerivation rec {
   name = "fsharp-${version}";
@@ -9,7 +11,7 @@ stdenv.mkDerivation rec {
     sha256 = "16kqgdx0y0lmxv59mc4g7l5ll60nixg5b8bg07vxfnqrf7i6dffd";
   };
 
-  buildInputs = [ mono pkgconfig autoconf automake which ];
+  buildInputs = [ mono pkgconfig dotnetbuildhelpers autoconf automake which ];
   configurePhase = ''
     substituteInPlace ./autogen.sh --replace "/usr/bin/env sh" "/bin/sh"
     ./autogen.sh --prefix $out
@@ -23,6 +25,10 @@ stdenv.mkDerivation rec {
     substituteInPlace $out/bin/fsharpiAnyCpu --replace " mono " " ${mono}/bin/mono "
     ln -s $out/bin/fsharpc $out/bin/fsc
     ln -s $out/bin/fsharpi $out/bin/fsi
+    for dll in "$out/lib/mono/4.5"/FSharp*.dll
+    do
+      create-pkg-config-for-dll.sh "$out/lib/pkgconfig" "$dll"
+    done
   '';
 
   # To fix this error when running:
diff --git a/pkgs/development/compilers/mono/default.nix b/pkgs/development/compilers/mono/default.nix
index ba2ce00cfb56..66939ff1a026 100644
--- a/pkgs/development/compilers/mono/default.nix
+++ b/pkgs/development/compilers/mono/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, bison, pkgconfig, glib, gettext, perl, libgdiplus, libX11, callPackage, ncurses, zlib, withLLVM ? true }:
+{ stdenv, fetchurl, bison, pkgconfig, glib, gettext, perl, libgdiplus, libX11, callPackage, ncurses, zlib, withLLVM ? false, cacert }:
 
 let
   llvm     = callPackage ./llvm.nix { };
@@ -31,11 +31,16 @@ stdenv.mkDerivation rec {
   # Parallel building doesn't work, as shows http://hydra.nixos.org/build/2983601
   enableParallelBuilding = false;
 
+  # We want pkg-config to take priority over the dlls in the Mono framework and the GAC
+  # because we control pkg-config
+  patches = [ ./pkgconfig-before-gac.patch ];
+
   # Patch all the necessary scripts. Also, if we're using LLVM, we fix the default
   # LLVM path to point into the Mono LLVM build, since it's private anyway.
   preBuild = ''
     makeFlagsArray=(INSTALL=`type -tp install`)
     patchShebangs ./
+    substituteInPlace mcs/class/corlib/System/Environment.cs --replace /usr/share "$out/share"
   '' + stdenv.lib.optionalString withLLVM ''
     substituteInPlace mono/mini/aot-compiler.c --replace "llvm_path = g_strdup (\"\")" "llvm_path = g_strdup (\"${llvm}/bin/\")"
   '';
@@ -50,6 +55,14 @@ stdenv.mkDerivation rec {
     done
   '';
 
+  # Without this, any Mono application attempting to open an SSL connection will throw with 
+  # The authentication or decryption has failed.
+  # ---> Mono.Security.Protocol.Tls.TlsException: Invalid certificate received from server.
+  postInstall = ''
+    echo "Updating Mono key store"
+    $out/bin/cert-sync ${cacert}/etc/ssl/certs/ca-bundle.crt
+  '';
+
   meta = {
     homepage = http://mono-project.com/;
     description = "Cross platform, open source .NET development framework";
diff --git a/pkgs/development/compilers/mono/pkgconfig-before-gac.patch b/pkgs/development/compilers/mono/pkgconfig-before-gac.patch
new file mode 100644
index 000000000000..7632d850391e
--- /dev/null
+++ b/pkgs/development/compilers/mono/pkgconfig-before-gac.patch
@@ -0,0 +1,65 @@
+diff -Naur mono-4.0.1.old/mcs/tools/xbuild/data/12.0/Microsoft.Common.targets mono-4.0.1/mcs/tools/xbuild/data/12.0/Microsoft.Common.targets
+--- mono-4.0.1.old/mcs/tools/x