lib: Split Darwin into macOS and iOS

I noticed LLVM accepts `ios` as its own OS in platform triples; a
recent change as far as I know. I see it also accepts `macos*` for macOS
(formerly OS X). If it's now customary to distinguish iOS like so
(rather than guessing from the aarch, lets add both so our OSes are
still disjoint, and make Darwin a family instead.

But changing the config everywhere would probably be a mass rebuild, and
I'm not sure how well other software supports OSes besides "darwin", so
I'm keeping that the default name for macOS for now.

2 files changed, 16 insertions, 6 deletions

diff --git a/lib/systems/inspect.nix b/lib/systems/inspect.nix
index ab220af46e30..4cdd26295471 100644
--- a/lib/systems/inspect.nix
+++ b/lib/systems/inspect.nix
@@ -21,9 +21,11 @@ rec {
     LittleEndian = { cpu = { significantByte = significantBytes.littleEndian; }; };
 
     BSD          = { kernel = { families = { inherit (kernelFamilies) bsd; }; }; };
+    Darwin       = { kernel = { families = { inherit (kernelFamilies) darwin; }; }; };
     Unix         = [ BSD Darwin Linux SunOS Hurd Cygwin ];
 
-    Darwin       = { kernel = kernels.darwin; };
+    MacOS        = { kernel = kernels.macos; };
+    iOS          = { kernel = kernels.ios; };
     Linux        = { kernel = kernels.linux; };
     SunOS        = { kernel = kernels.solaris; };
     FreeBSD      = { kernel = kernels.freebsd; };
diff --git a/lib/systems/parse.nix b/lib/systems/parse.nix
index 03d052f5f192..641a7f5d7584 100644
--- a/lib/systems/parse.nix
+++ b/lib/systems/parse.nix
@@ -134,6 +134,7 @@ rec {
 
   kernelFamilies = setTypes types.openKernelFamily {
     bsd = {};
+    darwin = {};
   };
 
   ################################################################################
@@ -149,7 +150,10 @@ rec {
   types.kernel = enum (attrValues kernels);
 
   kernels = with execFormats; with kernelFamilies; setTypes types.openKernel {
-    darwin  = { execFormat = macho;   families = { }; };
+    # TODO(@Ericson2314): Don't want to mass-rebuild yet to keeping 'darwin' as
+    # the nnormalized name for macOS.
+    macos   = { execFormat = macho;   families = { inherit darwin; }; name = "darwin"; };
+    ios     = { execFormat = macho;   families = { inherit darwin; }; };
     freebsd = { execFormat = elf;     families = { inherit bsd; }; };
     hurd    = { execFormat = elf;     families = { }; };
     linux   = { execFormat = elf;     families = { }; };
@@ -159,9 +163,13 @@ rec {
     solaris = { execFormat = elf;     families = { }; };
     windows = { execFormat = pe;      families = { }; };
   } // { # aliases
+    # 'darwin' is the kernel for all of them. We choose macOS by default.
+    darwin = kernels.macos;
     # TODO(@Ericson2314): Handle these Darwin version suffixes more generally.
-    darwin10 = kernels.darwin;
-    darwin14 = kernels.darwin;
+    darwin10 = kernels.macos;
+    darwin14 = kernels.macos;
+    watchos = kernels.ios;
+    tvos = kernels.ios;
     win32 = kernels.windows;
   };
 
@@ -263,8 +271,8 @@ rec {
   mkSystemFromString = s: mkSystemFromSkeleton (mkSkeletonFromList (lib.splitString "-" s));
 
   doubleFromSystem = { cpu, vendor, kernel, abi, ... }:
-    if abi == abis.cygnus
-    then "${cpu.name}-cygwin"
+    /**/ if abi == abis.cygnus       then "${cpu.name}-cygwin"
+    else if kernel.families ? darwin then "${cpu.name}-darwin"
     else "${cpu.name}-${kernel.name}";
 
   tripleFromSystem = { cpu, vendor, kernel, abi, ... } @ sys: assert isSystem sys; let