patch 8.1.1230: a lot of code is shared between vim.exe and gvim.exev8.1.1230

Problem:    A lot of code is shared between vim.exe and gvim.exe.
Solution:   Optionally put the shared code in vim.dll. (Ken Takata,
            closes #4287)

42 files changed, 1200 insertions, 466 deletions

diff --git a/.gitignore b/.gitignore
index 5691e22d00..6aa298b40f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,6 +33,8 @@ src/auto/pathdef.c
 *.suo
 *.res
 *.RES
+vim*.dll
+vim*.lib
 src/if_perl.c
 src/pathdef.c
 src/Obj*/pathdef.c
diff --git a/Filelist b/Filelist
index a6cc76c9f1..71892782f8 100644
--- a/Filelist
+++ b/Filelist
@@ -454,6 +454,7 @@ SRC_DOS =	\
 		src/iscygpty.h \
 		src/iid_ole.c \
 		src/os_dos.h \
+		src/os_w32dll.c \
 		src/os_w32exe.c \
 		src/os_win32.c \
 		src/os_mswin.c \
diff --git a/nsis/gvim.nsi b/nsis/gvim.nsi
index 2e990b8a05..5416a0f886 100644
--- a/nsis/gvim.nsi
+++ b/nsis/gvim.nsi
@@ -322,6 +322,9 @@ Section "$(str_section_exe)" id_section_exe
 
 	SetOutPath $0
 	File /oname=gvim.exe ${VIMSRC}\gvim_ole.exe
+!if /FileExists "${VIMSRC}\vim${BIT}.dll"
+	File ${VIMSRC}\vim${BIT}.dll
+!endif
 	File /oname=install.exe ${VIMSRC}\installw32.exe
 	File /oname=uninstal.exe ${VIMSRC}\uninstalw32.exe
 	File ${VIMSRC}\vimrun.exe
diff --git a/runtime/doc/gui_w32.txt b/runtime/doc/gui_w32.txt
index 15dd275a03..5ce3dc8c46 100644
--- a/runtime/doc/gui_w32.txt
+++ b/runtime/doc/gui_w32.txt
@@ -1,4 +1,4 @@
-*gui_w32.txt*   For Vim version 8.1.  Last change: 2017 Oct 27
+*gui_w32.txt*   For Vim version 8.1.  Last change: 2019 Apr 28
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -31,6 +31,17 @@ The GUI will always run in the Windows subsystem.  Mostly shells automatically
 return with a command prompt after starting gvim.  If not, you should use the
 "start" command: >
 	start gvim [options] file ..
+<							*E988*
+The console version with the |-g| option may also start the GUI by executing
+gvim.exe: >
+	vim -g [options] file ..
+To make this work, gvim.exe must exist in the same directory as the vim.exe,
+and this feature must be enabled at compile time.
+
+One may also use `:gui` from the console version.  However, this is an
+experimental feature and this feature must be enabled at compile time.
+It uses a session file to recreate the current state of the console Vim in the
+GUI Vim.
 
 Note: All fonts (bold, italic) must be of the same size!!!  If you don't do
 this, text will disappear or mess up the display.  Vim does not check the font
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 599b9eeb4c..a2ff64af20 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -36,7 +36,7 @@ FEATURES=HUGE
 DEBUG=no
 
 # set to yes to create a mapfile
-# MAP=yes
+#MAP=yes
 
 # set to SIZE for size, SPEED for speed, MAXSPEED for maximum optimization
 OPTIMIZE=MAXSPEED
@@ -44,6 +44,11 @@ OPTIMIZE=MAXSPEED
 # set to yes to make gvim, no for vim
 GUI=yes
 
+# set to yes to enable the DLL support (EXPERIMENTAL).
+# Creates vim{32,64}.dll, and stub gvim.exe and vim.exe.
+# "GUI" should be also set to "yes".
+#VIMDLL=yes
+
 # set to no if you do not want to use DirectWrite (DirectX)
 # MinGW-w64 is needed, and ARCH should be set to i686 or x86-64.
 DIRECTX=yes
@@ -687,7 +692,7 @@ else  # SPEED
 CFLAGS += -O2
 endif
 endif
-CFLAGS += -s
+LFLAGS += -s
 endif
 
 LIB = -lkernel32 -luser32 -lgdi32 -ladvapi32 -lcomdlg32 -lcomctl32 -lnetapi32 -lversion
@@ -739,7 +744,6 @@ OBJ = \
 	$(OUTDIR)/ops.o \
 	$(OUTDIR)/option.o \
 	$(OUTDIR)/os_mswin.o \
-	$(OUTDIR)/os_w32exe.o \
 	$(OUTDIR)/os_win32.o \
 	$(OUTDIR)/pathdef.o \
 	$(OUTDIR)/popupmnu.o \
@@ -760,10 +764,17 @@ OBJ = \
 	$(OUTDIR)/usercmd.o \
 	$(OUTDIR)/userfunc.o \
 	$(OUTDIR)/version.o \
-	$(OUTDIR)/vimrc.o \
 	$(OUTDIR)/winclip.o \
 	$(OUTDIR)/window.o
 
+ifeq ($(VIMDLL),yes)
+OBJ += $(OUTDIR)/os_w32dll.o $(OUTDIR)/vimrcd.o
+EXEOBJC = $(OUTDIR)/os_w32exec.o $(OUTDIR)/vimrcc.o
+EXEOBJG = $(OUTDIR)/os_w32exeg.o $(OUTDIR)/vimrcg.o
+else
+OBJ += $(OUTDIR)/os_w32exe.o $(OUTDIR)/vimrc.o
+endif
+
 ifdef PERL
 OBJ += $(OUTDIR)/if_perl.o
 endif
@@ -870,16 +881,36 @@ endif
 
 LFLAGS += -municode
 
-ifeq ($(GUI),yes)
+ifeq ($(VIMDLL),yes)
+VIMEXE := vim$(DEBUG_SUFFIX).exe
+GVIMEXE := gvim$(DEBUG_SUFFIX).exe
+ ifeq ($(ARCH),x86-64)
+VIMDLLBASE := vim64$(DEBUG_SUFFIX)
+ else
+VIMDLLBASE := vim32$(DEBUG_SUFFIX)
+ endif
+TARGET = $(VIMDLLBASE).dll
+LFLAGS += -shared
+EXELFLAGS += -municode
+ ifneq ($(DEBUG),yes)
+EXELFLAGS += -s
+ endif
+DEFINES += $(DEF_GUI) -DVIMDLL
+OBJ += $(GUIOBJ) $(CUIOBJ)
+OUTDIR = dobj$(DEBUG_SUFFIX)$(MZSCHEME_SUFFIX)$(ARCH)
+MAIN_TARGET = $(GVIMEXE) $(VIMEXE) $(VIMDLLBASE).dll
+else ifeq ($(GUI),yes)
 TARGET := gvim$(DEBUG_SUFFIX).exe
 DEFINES += $(DEF_GUI)
 OBJ += $(GUIOBJ)
 LFLAGS += -mwindows
 OUTDIR = gobj$(DEBUG_SUFFIX)$(MZSCHEME_SUFFIX)$(ARCH)
+MAIN_TARGET = $(TARGET)
 else
 OBJ += $(CUIOBJ)
 TARGET := vim$(DEBUG_SUFFIX).exe
 OUTDIR = obj$(DEBUG_SUFFIX)$(MZSCHEME_SUFFIX)$(ARCH)
+MAIN_TARGET = $(TARGET)
 endif
 
 ifdef GETTEXT
@@ -955,7 +986,7 @@ ifeq (yes, $(MAP))
 LFLAGS += -Wl,-Map=$(TARGET).map
 endif
 
-all: $(TARGET) vimrun.exe xxd/xxd.exe tee/tee.exe install.exe uninstal.exe GvimExt/gvimext.dll
+all: $(MAIN_TARGET) vimrun.exe xxd/xxd.exe tee/tee.exe install.exe uninstal.exe GvimExt/gvimext.dll
 
 vimrun.exe: vimrun.c
 	$(CC) $(CFLAGS) -o vimrun.exe vimrun.c $(LIB)
@@ -966,8 +997,19 @@ install.exe: dosinst.c
 uninstal.exe: uninstal.c
 	$(CC) $(CFLAGS) -o uninstal.exe uninstal.c $(LIB)
 
+ifeq ($(VIMDLL),yes)
+$(TARGET): $(OUTDIR) $(OBJ)
+	$(LINK) $(CFLAGS) $(LFLAGS) -o $@ $(OBJ) $(LIB) -lole32 -luuid -lgdi32 $(LUA_LIB) $(MZSCHEME_LIBDIR) $(MZSCHEME_LIB) $(PYTHONLIB) $(PYTHON3LIB) $(RUBYLIB)
+
+$(GVIMEXE): $(OUTDIR) $(EXEOBJG) $(VIMDLLBASE).dll
+	$(CC) -L. $(EXELFLAGS) -mwindows -o $@ $(EXEOBJG) -l$(VIMDLLBASE)
+
+$(VIMEXE): $(OUTDIR) $(EXEOBJC) $(VIMDLLBASE).dll
+	$(CC) -L. $(EXELFLAGS) -o $@ $(EXEOBJC) -l$(VIMDLLBASE)
+else
 $(TARGET): $(OUTDIR) $(OBJ)
 	$(LINK) $(CFLAGS) $(LFLAGS) -o $@ $(OBJ) $(LIB) -lole32 -luuid $(LUA_LIB) $(MZSCHEME_LIBDIR) $(MZSCHEME_LIB) $(PYTHONLIB) $(PYTHON3LIB) $(RUBYLIB)
+endif
 
 upx: exes
 	upx gvim.exe
@@ -996,7 +1038,7 @@ clean:
 	-$(DEL) $(OUTDIR)$(DIRSLASH)*.o
 	-$(DEL) $(OUTDIR)$(DIRSLASH)*.res
 	-rmdir $(OUTDIR)
-	-$(DEL) $(TARGET) vimrun.exe install.exe uninstal.exe
+	-$(DEL) $(MAIN_TARGET) vimrun.exe install.exe uninstal.exe
 	-$(DEL) pathdef.c
 ifdef PERL
 	-$(DEL) if_perl.c
@@ -1025,74 +1067,95 @@ $(OUTDIR)/if_python3.o:	if_python3.c if_py_both.h $(INCL)
 $(OUTDIR)/%.o : %.c $(INCL)
 	$(CC) -c $(CFLAGS) $< -o $@
 
-$(OUTDIR)/vimrc.o:	vim.rc version.h gui_w32_rc.h
+ifeq ($(VIMDLL),yes)
+$(OUTDIR)/vimrcc.o:	vim.rc gvim.exe.mnf version.h gui_w32_rc.h vim.ico
+	$(WINDRES) $(WINDRES_FLAGS) $(DEFINES) -UFEAT_GUI_MSWIN \
+	    --input-format=rc --output-format=coff -i vim.rc -o $@
+
+$(OUTDIR)/vimrcg.o:	vim.rc gvim.exe.mnf version.h gui_w32_rc.h vim.ico
+	$(WINDRES) $(WINDRES_FLAGS) $(DEFINES) \
+	    --input-format=rc --output-format=coff -i vim.rc -o $@
+
+$(OUTDIR)/vimrcd.o:	vim.rc version.h gui_w32_rc.h \
+			tools.bmp tearoff.bmp vim.ico vim_error.ico \
+			vim_alert.ico vim_info.ico vim_quest.ico
+	$(WINDRES) $(WINDRES_FLAGS) $(DEFINES) -DRCDLL -DVIMDLLBASE=\\\"$(VIMDLLBASE)\\\" \
+	    --input-format=rc --output-format=coff -i vim.rc -o $@
+else
+$(OUTDIR)/vimrc.o:	vim.rc gvim.exe.mnf version.h gui_w32_rc.h \
+			tools.bmp tearoff.bmp vim.ico vim_error.ico \
+			vim_alert.ico vim_info.ico vim_quest.ico
 	$(WINDRES) $(WINDRES_FLAGS) $(DEFINES) \
 	    --input-format=rc --output-format=coff -i vim.rc -o $@
+endif
 
 $(OUTDIR):
 	$(MKDIR) $(OUTDIR)
 
 $(OUTDIR)/gui_dwrite.o:	gui_dwrite.cpp $(INCL) gui_dwrite.h
-	$(CC) -c $(CFLAGS) $(CXXFLAGS) gui_dwrite.cpp -o $(OUTDIR)/gui_dwrite.o
+	$(CC) -c $(CFLAGS) $(CXXFLAGS) gui_dwrite.cpp -o $@
 
 $(OUTDIR)/gui.o:	gui.c $(INCL) $(GUI_INCL)
-	$(CC) -c $(CFLAGS) gui.c -o $(OUTDIR)/gui.o
+	$(CC) -c $(CFLAGS) gui.c -o $@
 
 $(OUTDIR)/beval.o:	beval.c $(INCL) $(GUI_INCL)
-	$(CC) -c $(CFLAGS) beval.c -o $(OUTDIR)/beval.o
+	$(CC) -c $(CFLAGS) beval.c -o $@
 
 $(OUTDIR)/gui_beval.o:	gui_beval.c $(INCL) $(GUI_INCL)
-	$(CC) -c $(CFLAGS) gui_beval.c -o $(OUTDIR)/gui_beval.o
+	$(CC) -c $(CFLAGS) gui_beval.c -o $@
 
 $(OUTDIR)/gui_w32.o:	gui_w32.c $(INCL) $(GUI_INCL)
-	$(CC) -c $(CFLAGS) gui_w32.c -o $(OUTDIR)/gui_w32.o
+	$(CC) -c $(CFLAGS) gui_w32.c -o $@
 
 $(OUTDIR)/if_cscope.o:	if_cscope.c $(INCL) if_cscope.h
-	$(CC) -c $(CFLAGS) if_cscope.c -o $(OUTDIR)/if_cscope.o
+	$(CC) -c $(CFLAGS) if_cscope.c -o $@
 
 $(OUTDIR)/if_mzsch.o:	if_mzsch.c $(INCL) $(MZSCHEME_INCL) $(MZ_EXTRA_DEP)
-	$(CC) -c $(CFLAGS) if_mzsch.c -o $(OUTDIR)/if_mzsch.o
+	$(CC) -c $(CFLAGS) if_mzsch.c -o $@
 
 mzscheme_base.c:
 	$(MZSCHEME)/mzc --c-mods mzscheme_base.c ++lib scheme/base
 
 # Remove -D__IID_DEFINED__ for newer versions of the w32api
 $(OUTDIR)/if_ole.o:	if_ole.cpp $(INCL) if_ole.h
-	$(CC) $(CFLAGS) $(CXXFLAGS) -c -o $(OUTDIR)/if_ole.o if_ole.cpp
+	$(CC) -c $(CFLAGS) $(CXXFLAGS) if_ole.cpp -o $@
 
 auto/if_perl.c:		if_perl.xs typemap
 	$(XSUBPP) -prototypes -typemap \
 	     $(PERLTYPEMAP) if_perl.xs -output $@
 
 $(OUTDIR)/if_perl.o:	auto/if_perl.c $(INCL)
-	$(CC) -c $(CFLAGS) auto/if_perl.c -o $(OUTDIR)/if_perl.o
+	$(CC) -c $(CFLAGS) auto/if_perl.c -o $@
 
 
 $(OUTDIR)/if_ruby.o:	if_ruby.c $(INCL)
 ifeq (16, $(RUBY))
-	$(CC) $(CFLAGS) -U_WIN32 -c -o $(OUTDIR)/if_ruby.o if_ruby.c
+	$(CC) $(CFLAGS) -U_WIN32 -c -o $@ if_ruby.c
 endif
 
 $(OUTDIR)/iscygpty.o:	iscygpty.c $(CUI_INCL)
 	$(CC) -c $(CFLAGS) iscygpty.c -o $(OUTDIR)/iscygpty.o -U_WIN32_WINNT -D_WIN32_WINNT=0x0600 -DUSE_DYNFILEID -DENABLE_STUB_IMPL
 
 $(OUTDIR)/main.o:	main.c $(INCL) $(CUI_INCL)
-	$(CC) -c $(CFLAGS) main.c -o $(OUTDIR)/main.o
+	$(CC) -c $(CFLAGS) main.c -o $@
 
 $(OUTDIR)/netbeans.o:	netbeans.c $(INCL) $(NBDEBUG_INCL) $(NBDEBUG_SRC)
-	$(CC) -c $(CFLAGS) netbeans.c -o $(OUTDIR)/netbeans.o
+	$(CC) -c $(CFLAGS) netbeans.c -o $@
+
+$(OUTDIR)/os_w32exec.o:	os_w32exe.c $(INCL)
+	$(CC) -c $(CFLAGS) -UFEAT_GUI_MSWIN os_w32exe.c -o $@
+
+$(OUTDIR)/os_w32exeg.o:	os_w32exe.c $(INCL)
+	$(CC) -c $(CFLAGS) os_w32exe.c -o $@
 
 $(OUTDIR)/os_win32.o:	os_win32.c $(INCL) $(MZSCHEME_INCL)
-	$(CC) -c $(CFLAGS) os_win32.c -o $(OUTDIR)/os_win32.o
+	$(CC) -c $(CFLAGS) os_win32.c -o $@
 
 $(OUTDIR)/regexp.o:	regexp.c regexp_nfa.c $(INCL)
-	$(CC) -c $(CFLAGS) regexp.c -o $(OUTDIR)/regexp.o
+	$(CC) -c $(CFLAGS) regexp.c -o $@
 
 $(OUTDIR)/terminal.o:	terminal.c $(INCL) $(TERM_DEPS)
-	$(CC) -c $(CFLAGS) terminal.c -o $(OUTDIR)/terminal.o
-
-$(OUTDIR)/textprop.o:	textprop.c $(INCL)
-	$(CC) -c $(CFLAGS) textprop.c -o $(OUTDIR)/textprop.o
+	$(CC) -c $(CFLAGS) terminal.c -o $@
 
 
 CCCTERM = $(CC) -c $(CFLAGS) -Ilibvterm/include -DINLINE="" \
@@ -1100,50 +1163,13 @@ CCCTERM = $(CC) -c $(CFLAGS) -Ilibvterm/include -DINLINE="" \
 	  -DIS_COMBINING_FUNCTION=utf_iscomposing_uint \
 	  -DWCWIDTH_FUNCTION=utf_uint2cells
 
-$(OUTDIR)/encoding.o: libvterm/src/encoding.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/encoding.c -o $@
-
-$(OUTDIR)/keyboard.o: libvterm/src/keyboard.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/keyboard.c -o $@
-
-$(OUTDIR)/mouse.o: libvterm/src/mouse.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/mouse.c -o $@
-
-$(OUTDIR)/parser.o: libvterm/src/parser.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/parser.c -o $@
-
-$(OUTDIR)/pen.o: libvterm/src/pen.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/pen.c -o $@
+$(OUTDIR)/%.o : libvterm/src/%.c $(TERM_DEPS)
+	$(CCCTERM) $< -o $@
 
-$(OUTDIR)/termscreen.o: libvterm/src/termscreen.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/termscreen.c -o $@
 
-$(OUTDIR)/state.o: libvterm/src/state.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/state.c -o $@
-
-$(OUTDIR)/unicode.o: libvterm/src/unicode.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/unicode.c -o $@
-
-$(OUTDIR)/vterm.o: libvterm/src/vterm.c $(TERM_DEPS)
-	$(CCCTERM) libvterm/src/vterm.c -o $@
-
-$(OUTDIR)/xdiffi.o: xdiff/xdiffi.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xdiffi.c -o $(OUTDIR)/xdiffi.o
-
-$(OUTDIR)/xemit.o: xdiff/xemit.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xemit.c -o $(OUTDIR)/xemit.o
-
-$(OUTDIR)/xprepare.o: xdiff/xprepare.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xprepare.c -o $(OUTDIR)/xprepare.o
-
-$(OUTDIR)/xutils.o: xdiff/xutils.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xutils.c -o $(OUTDIR)/xutils.o
-
-$(OUTDIR)/xhistogram.o: xdiff/xhistogram.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xhistogram.c -o $(OUTDIR)/xhistogram.o
+$(OUTDIR)/%.o : xdiff/%.c $(XDIFF_DEPS)
+	$(CC) -c $(CFLAGS) $< -o $@
 
-$(OUTDIR)/xpatience.o: xdiff/xpatience.c $(XDIFF_DEPS)
-	$(CC) -c $(CFLAGS) xdiff/xpatience.c -o $(OUTDIR)/xpatience.o
 
 pathdef.c: $(INCL)
 ifneq (sh.exe, $(SHELL))
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index ef2b7f3f9d..07ebb75592 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -40,6 +40,12 @@
 #
 #       Terminal support: TERMINAL=yes (default is yes)
 #
+#	DLL support (EXPERIMENTAL): VIMDLL=yes (default is no)
+#	  Creates vim{32,64}.dll, and stub gvim.exe and vim.exe.
+#	  The shared codes between the GUI and the console are built into
+#	  the DLL.  This reduces the total file size and memory usage.
+#	  Also supports `vim -g` and the `:gui` command.
+#
 #	Lua interface:
 #	  LUA=[Path to Lua directory]
 #	  DYNAMIC_LUA=yes (to load the Lua DLL dynamically)
@@ -178,6 +184,10 @@
 
 TARGETOS = WINNT
 
+!if "$(VIMDLL)" == "yes"
+GUI = yes
+!endif
+
 !ifndef DIRECTX
 DIRECTX = $(GUI)
 !endif
@@ -185,7 +195,9 @@ DIRECTX = $(GUI)
 # Select one of eight object code directories, depends on GUI, OLE, DEBUG and
 # interfaces.
 # If you change something else, do "make clean" first!
-!if "$(GUI)" == "yes"
+!if "$(VIMDLL)" == "yes"
+OBJDIR = .\ObjD
+!elseif "$(GUI)" == "yes"
 OBJDIR = .\ObjG
 !else
 OBJDIR = .\ObjC
@@ -410,7 +422,7 @@ CHANNEL = $(GUI)
 !endif
 !endif
 
-# GUI sepcific features.
+# GUI specific features.
 !if "$(GUI)" == "yes"
 # Only allow NETBEANS for a GUI build and CHANNEL.
 !if "$(NETBEANS)" == "yes" && "$(CHANNEL)" == "yes"
@@ -461,7 +473,7 @@ XPM = no
 XPM_OBJ   = $(OBJDIR)/xpm_w32.obj
 XPM_DEFS  = -DFEAT_XPM_W32
 !if $(MSVC_MAJOR) >= 14
-# VC14 cannot use a library built by VC12 or eariler, because VC14 uses
+# VC14 cannot use a library built by VC12 or earlier, because VC14 uses
 # Universal CRT.
 XPM_LIB   = $(XPM)\lib-vc14\libXpm.lib
 !else
@@ -566,7 +578,7 @@ CPUARG =
 # VC<11 generates fp87 code by default
 !  if $(MSVC_MAJOR) < 11
 CPUARG =
-# VC>=11 needs explicit insturctions to generate fp87 code
+# VC>=11 needs explicit instructions to generate fp87 code
 !  else
 CPUARG = /arch:IA32
 !  endif
@@ -612,6 +624,17 @@ CPUARG = /arch:AVX2
 # Pass CPUARG to GvimExt, to avoid using version-dependent defaults
 MAKEFLAGS_GVIMEXT = $(MAKEFLAGS_GVIMEXT) CPUARG="$(CPUARG)"
 
+!if "$(VIMDLL)" == "yes"
+VIMDLLBASE = vim
+! if "$(ASSEMBLY_ARCHITECTURE)" == "i386"
+VIMDLLBASE = $(VIMDLLBASE)32
+! else
+VIMDLLBASE = $(VIMDLLBASE)64
+! endif
+! if "$(DEBUG)" == "yes"
+VIMDLLBASE = $(VIMDLLBASE)d
+! endif
+!endif
 
 LIBC =
 DEBUGINFO = /Zi
@@ -747,7 +770,6 @@ OBJ = \
 	$(OUTDIR)\ops.obj \
 	$(OUTDIR)\option.obj \
 	$(OUTDIR)\os_mswin.obj \
-	$(OUTDIR)\os_w32exe.obj \
 	$(OUTDIR)\os_win32.obj \
 	$(OUTDIR)\pathdef.obj \
 	$(OUTDIR)\popupmnu.obj \
@@ -769,7 +791,15 @@ OBJ = \
 	$(OUTDIR)\userfunc.obj \
 	$(OUTDIR)\winclip.obj \
 	$(OUTDIR)\window.obj \
-	$(OUTDIR)\vim.res
+
+!if "$(VIMDLL)" == "yes"
+OBJ = $(OBJ) $(OUTDIR)\os_w32dll.obj $(OUTDIR)\vimd.res
+EXEOBJC = $(OUTDIR)\os_w32exec.obj $(OUTDIR)\vimc.res
+EXEOBJG = $(OUTDIR)\os_w32exeg.obj $(OUTDIR)\vimg.res
+CFLAGS = $(CFLAGS) -DVIMDLL
+!else
+OBJ = $(OBJ) $(OUTDIR)\os_w32exe.obj $(OUTDIR)\vim.res
+!endif
 
 !if "$(OLE)" == "yes"
 CFLAGS = $(CFLAGS) -DFEAT_OLE
@@ -800,7 +830,15 @@ OBJ = $(OBJ) $(OUTDIR)\dimm_i.obj $(OUTDIR)\glbl_ime.obj
 SUBSYSTEM = windows
 CFLAGS = $(CFLAGS) -DFEAT_GUI_MSWIN
 RCFLAGS = $(RCFLAGS) -DFEAT_GUI_MSWIN
+! if "$(VIMDLL)" == "yes"
+SUBSYSTEM_CON = console
+GVIM = g$(VIM)
+CUI_INCL = iscygpty.h
+CUI_OBJ = $(OUTDIR)\iscygpty.obj
+RCFLAGS = $(RCFLAGS) -DVIMDLL
+! else
 VIM = g$(VIM)
+! endif
 GUI_INCL = \
 	gui.h
 GUI_OBJ = \
@@ -839,6 +877,9 @@ XDIFF_DEPS = \
 !if "$(SUBSYSTEM_VER)" != ""
 SUBSYSTEM = $(SUBSYSTEM),$(SUBSYSTEM_VER)
 SUBSYSTEM_TOOLS = $(SUBSYSTEM_TOOLS),$(SUBSYSTEM_VER)
+! if "$(VIMDLL)" != "yes"
+SUBSYSTEM_CON = $(SUBSYSTEM_CON),$(SUBSYSTEM_VER)
+! endif
 # Pass SUBSYSTEM_VER to GvimExt and other tools
 MAKEFLAGS_GVIMEXT = $(MAKEFLAGS_GVIMEXT) SUBSYSTEM_VER=$(SUBSYSTEM_VER)
 MAKEFLAGS_TOOLS = $(MAKEFLAGS_TOOLS) SUBSYSTEM_VER=$(SUBSYSTEM_VER)
@@ -1174,7 +1215,11 @@ CFLAGS = $(CFLAGS) -DFEAT_$(FEATURES)
 # debug more conveniently (able to look at variables which are in registers)
 #
 CFLAGS = $(CFLAGS) /Fd$(OUTDIR)/ $(DEBUGINFO)
+!if "$(VIMDLL)" == "yes"
+LINK_PDB = /PDB:$(VIMDLLBASE).pdb -debug
+!else
 LINK_PDB = /PDB:$(VIM).pdb -debug
+!endif
 
 #
 # End extra feature include
@@ -1186,7 +1231,7 @@ CFLAGS_OUTDIR=$(CFLAGS) /Fo$(OUTDIR)/
 
 # Add /opt:ref to remove unreferenced functions and data even when /DEBUG is
 # added.
-conflags = /nologo /subsystem:$(SUBSYSTEM) /opt:ref
+conflags = /nologo /opt:ref
 
 PATHDEF_SRC = $(OUTDIR)\pathdef.c
 
@@ -1219,7 +1264,13 @@ LINKARGS1 = $(LINKARGS1) /LTCG:STATUS
 LINKARGS1 = $(LINKARGS1) /HIGHENTROPYVA:NO
 !endif
 
-all:	$(VIM).exe \
+!if "$(VIMDLL)" == "yes"
+MAIN_TARGET = $(GVIM).exe $(VIM).exe $(VIMDLLBASE).dll
+!else
+MAIN_TARGET = $(VIM).exe
+!endif
+
+all:	$(MAIN_TARGET) \
 	vimrun.exe \
 	install.exe \
 	uninstal.exe \
@@ -1227,17 +1278,41 @@ all:	$(VIM).exe \
 	tee/tee.exe \
 	GvimExt/gvimext.dll
 
+!if "$(VIMDLL)" == "yes"
+
+$(VIMDLLBASE).dll: $(OUTDIR) $(OBJ) $(XDIFF_OBJ) $(GUI_OBJ) $(CUI_OBJ) $(OLE_OBJ) $(OLE_IDL) $(MZSCHEME_OBJ) \
+		$(LUA_OBJ) $(PERL_OBJ) $(PYTHON_OBJ) $(PYTHON3_OBJ) $(RUBY_OBJ) $(TCL_OBJ) \
+		$(CSCOPE_OBJ) $(TERM_OBJ) $(NETBEANS_OBJ) $(CHANNEL_OBJ) $(XPM_OBJ) \
+		version.c version.h
+	$(CC) $(CFLAGS_OUTDIR) version.c
+	$(link) $(LINKARGS1) /dll -out:$(VIMDLLBASE).dll $(OBJ) $(XDIFF_OBJ) $(GUI_OBJ) $(CUI_OBJ) $(OLE_OBJ) \
+		$(LUA_OBJ) $(MZSCHEME_OBJ) $(PERL_OBJ) $(PYTHON_OBJ) $(PYTHON3_OBJ) $(RUBY_OBJ) \
+		$(TCL_OBJ) $(CSCOPE_OBJ) $(TERM_OBJ) $(NETBEANS_OBJ) $(CHANNEL_OBJ) \
+		$(XPM_OBJ) $(OUTDIR)\version.obj $(LINKARGS2)
+
+$(GVIM).exe: $(OUTDIR) $(EXEOBJG) $(VIMDLLBASE).dll
+	$(link) $(LINKARGS1) /subsystem:$(SUBSYSTEM) -out:$(GVIM).exe $(EXEOBJG) $(VIMDLLBASE).lib $(LIBC)
+	if exist $(GVIM).exe.manifest mt.exe -nologo -manifest $(GVIM).exe.manifest -updateresource:$(GVIM).exe;1
+
+$(VIM).exe: $(OUTDIR) $(EXEOBJC) $(VIMDLLBASE).dll
+	$(link) $(LINKARGS1) /subsystem:$(SUBSYSTEM_CON) -out:$(VIM).exe $(EXEOBJC) $(VIMDLLBASE).lib $(LIBC)
+	if exist $(VIM).exe.manifest mt.exe -nologo -manifest $(VIM).exe.manifest -updateresource:$(VIM).exe;1
+
+!else
+
 $(VIM).exe: $(OUTDIR) $(OBJ) $(XDIFF_OBJ) $(GUI_OBJ) $(CUI_OBJ) $(OLE_OBJ) $(OLE_IDL) $(MZSCHEME_OBJ) \
 		$(LUA_OBJ) $(PERL_OBJ) $(PYTHON_OBJ) $(PYTHON3_OBJ) $(RUBY_OBJ) $(TCL_OBJ) \
 		$(CSCOPE_OBJ) $(TERM_OBJ) $(NETBEANS_OBJ) $(CHANNEL_OBJ) $(XPM_OBJ) \
 		version.c version.h
 	$(CC) $(CFLAGS_OUTDIR) version.c
-	$(link) $(LINKARGS1) -out:$(VIM).exe $(OBJ) $(XDIFF_OBJ) $(GUI_OBJ) $(CUI_OBJ) $(OLE_OBJ) \
+	$(link) $(LINKARGS1) /subsystem:$(SUBSYSTEM) -out:$(VIM).exe $(OBJ) $(XDIFF_OBJ) $(GUI_OBJ) $(CUI_OBJ) $(OLE_OBJ) \
 		$(LUA_OBJ) $(MZSCHEME_OBJ) $(PERL_OBJ) $(PYTHON_OBJ) $(PYTHON3_OBJ) $(RUBY_OBJ) \
 		$(TCL_OBJ) $(CSCOPE_OBJ) $(TERM_OBJ) $(NETBEANS_OBJ) $(CHANNEL_OBJ) \
 		$(XPM_OBJ) $(OUTDIR)\version.obj $(LINKARGS2)
 	if exist $(VIM).exe.manifest mt.exe -nologo -manifest $(VIM).exe.manifest -updateresource:$(VIM).exe;1
 
+!endif
+
 $(VIM): $(VIM).exe
 
 $(OUTDIR):
@@ -1287,6 +1362,15 @@ clean:
 	- if exist $(VIM).pdb del $(VIM).pdb
 	- if exist $(VIM).map del $(VIM).map
 	- if exist $(VIM).ncb del $(VIM).ncb
+!if "$(VIMDLL)" == "yes"
+	- if exist $(GVIM).exe del $(GVIM).exe
+	- if exist $(GVIM).map del $(GVIM).map
+	- if exist $(VIMDLLBASE).dll del $(VIMDLLBASE).dll
+	- if exist $(VIMDLLBASE).lib del $(VIMDLLBASE).lib
+	- if exist $(VIMDLLBASE).exp del $(VIMDLLBASE).exp
+	- if exist $(VIMDLLBASE).pdb del $(VIMDLLBASE).pdb
+	- if exist $(VIMDLLBASE).map del $(VIMDLLBASE).map
+!endif
 	- if exist vimrun.exe del vimrun.exe
 	- if exist install.exe del install.exe
 	- if exist uninstal.exe del uninstal.exe
@@ -1334,21 +1418,15 @@ $(NEW_TESTS):
 ###########################################################################
 
 # Create a default rule for transforming .c files to .obj files in $(OUTDIR)
-# Batch compilation is supported by nmake 1.62 (part of VS 5.0) and later)
-!IF "$(_NMAKE_VER)" == ""
-.c{$(OUTDIR)/}.obj:
-!ELSE
 .c{$(OUTDIR)/}.obj::
-!ENDIF
+	$(CC) $(CFLAGS_OUTDIR) $<
+
+# Create a default rule for xdiff.
+{xdiff/}.c{$(OUTDIR)/}.obj::
 	$(CC) $(CFLAGS_OUTDIR) $<
 
 # Create a default rule for transforming .cpp files to .obj files in $(OUTDIR)
-# Batch compilation is supported by nmake 1.62 (part of VS 5.0) and later)
-!IF "$(_NMAKE_VER)" == ""
-.cpp{$(OUTDIR)/}.obj:
-!ELSE
 .cpp{$(OUTDIR)/}.obj::
-!ENDIF
 	$(CC) $(CFLAGS_OUTDIR) $<
 
 $(OUTDIR)/arabic.obj:	$(OUTDIR) arabic.c  $(INCL)
@@ -1376,22 +1454,16 @@ $(OUTDIR)/dict.obj:	$(OUTDIR) dict.c  $(INCL)
 $(OUTDIR)/diff.obj:	$(OUTDIR) diff.c  $(INCL)
 
 $(OUTDIR)/xdiffi.obj:	$(OUTDIR) xdiff/xdiffi.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xdiffi.c 
 
 $(OUTDIR)/xemit.obj:	$(OUTDIR) xdiff/xemit.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xemit.c 
 
 $(OUTDIR)/xprepare.obj:	$(OUTDIR) xdiff/xprepare.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xprepare.c 
 
 $(OUTDIR)/xutils.obj:	$(OUTDIR) xdiff/xutils.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xutils.c 
 
 $(OUTDIR)/xhistogram.obj:	$(OUTDIR) xdiff/xhistogram.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xhistogram.c 
 
 $(OUTDIR)/xpatience.obj:	$(OUTDIR) xdiff/xpatience.c  $(XDIFF_DEPS)
-	$(CC) $(CFLAGS_OUTDIR) xdiff/xpatience.c 
 
 $(OUTDIR)/digraph.obj:	$(OUTDIR) digraph.c  $(INCL)
 
@@ -1516,8 +1588,16 @@ $(OUTDIR)/winclip.obj:	$(OUTDIR) winclip.c  $(INCL)
 
 $(OUTDIR)/os_win32.obj:	$(OUTDIR) os_win32.c  $(INCL) $(MZSCHEME_INCL)
 
+$(OUTDIR)/os_w32dll.obj:	$(OUTDIR) os_w32dll.c
+
 $(OUTDIR)/os_w32exe.obj:	$(OUTDIR) os_w32exe.c  $(INCL)
 
+$(OUTDIR)/os_w32exec.obj:	$(OUTDIR) os_w32exe.c  $(INCL)
+	$(CC) $(CFLAGS:-DFEAT_GUI_MSWIN=) /Fo$@ os_w32exe.c
+
+$(OUTDIR)/os_w32exeg.obj:	$(OUTDIR) os_w32exe.c  $(INCL)
+	$(CC) $(CFLAGS) /Fo$@ os_w32exe.c
+
 $(OUTDIR)/pathdef.obj:	$(OUTDIR) $(PATHDEF_SRC) $(INCL)
 	$(CC) $(CFLAGS_OUTDIR) $(PATHDEF_SRC)
 
@@ -1560,10 +1640,25 @@ $(OUTDIR)/window.obj:	$(OUTDIR) window.c  $(INCL)
 $(OUTDIR)/xpm_w32.obj: $(OUTDIR) xpm_w32.c
 	$(CC) $(CFLAGS_OUTDIR) $(XPM_INC) xpm_w32.c
 
-$(OUTDIR)/vim.res:	$(OUTDIR) vim.rc gvim.exe.mnf version.h tools.bmp \
-				tearoff.bmp vim.ico vim_error.ico \
+!if "$(VIMDLL)" == "yes"
+$(OUTDIR)/vimc.res:	$(OUTDIR) vim.rc gvim.exe.mnf version.h gui_w32_rc.h \
+				vim.ico
+	$(RC) /nologo /l 0x409 /Fo$@ $(RCFLAGS:-DFEAT_GUI_MSWIN=) vim.rc
+
+$(OUTDIR)/vimg.res:	$(OUTDIR) vim.rc gvim.exe.mnf version.h gui_w32_rc.h \
+				vim.ico
+	$(RC) /nologo /l 0x409 /Fo$@ $(RCFLAGS) vim.rc
+
+$(OUTDIR)/vimd.res:	$(OUTDIR) vim.rc version.h gui_w32_rc.h \
+				tools.bmp tearoff.bmp vim.ico vim_error.ico \
+				vim_alert.ico vim_info.ico vim_quest.ico
+	$(RC) /nologo /l 0x409 /Fo$@ $(RCFLAGS) -DRCDLL -DVIMDLLBASE=\"$(VIMDLLBASE)\" vim.rc
+!else
+$(OUTDIR)/vim.res:	$(OUTDIR) vim.rc gvim.exe.mnf version.h gui_w32_rc.h \
+				tools.bmp tearoff.bmp vim.ico vim_error.ico \
 				vim_alert.ico vim_info.ico vim_quest.ico
-	$(RC) /nologo /l 0x409 /Fo$(OUTDIR)/vim.res $(RCFLAGS) vim.rc
+	$(RC) /nologo /l 0x409 /Fo$@ $(RCFLAGS) vim.rc
+!endif
 
 iid_ole.c if_ole.h vim.tlb: if_ole.idl
 	midl /nologo /error none /proxy nul /iid iid_ole.c /tlb vim.tlb \
@@ -1583,32 +1678,27 @@ CCCTERM = $(CC) $(CFLAGS) -Ilibvterm/include -DINLINE="" \
 	-DWCWIDTH_FUNCTION=utf_uint2cells \
 	-D_CRT_SECURE_NO_WARNINGS
 
+# Create a default rule for libvterm.
+{libvterm/src/}.c{$(OUTDIR)/}.obj::
+	$(CCCTERM) -Fo$(OUTDIR)/ $<
+
 $(OUTDIR)/encoding.obj: $(OUTDIR) libvterm/src/encoding.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/encoding.c
 
 $(OUTDIR)/keyboard.obj: $(OUTDIR) libvterm/src/keyboard.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/keyboard.c
 
 $(OUTDIR)/mouse.obj: $(OUTDIR) libvterm/src/mouse.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/mouse.c
 
 $(OUTDIR)/parser.obj: $(OUTDIR) libvterm/src/parser.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/parser.c
 
 $(OUTDIR)/pen.obj: $(OUTDIR) libvterm/src/pen.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/pen.c
 
 $(OUTDIR)/termscreen.obj: $(OUTDIR) libvterm/src/termscreen.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/termscreen.c
 
 $(OUTDIR)/state.obj: $(OUTDIR) libvterm/src/state.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/state.c
 
 $(OUTDIR)/unicode.obj: $(OUTDIR) libvterm/src/unicode.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/unicode.c
 
 $(OUTDIR)/vterm.obj: $(OUTDIR) libvterm/src/vterm.c $(TERM_DEPS)
-	$(CCCTERM) -Fo$@ libvterm/src/vterm.c
 
 
 # $CFLAGS may contain backslashes and double quotes, escape them both.
diff --git a/src/channel.c b/src/channel.c
index ca8310258e..aac8656cf1 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -5319,7 +5319,7 @@ job_still_useful(job_T *job)
     return job_need_end_check(job) || job_channel_still_useful(job);
 }
 
-#if defined(GUI_MAY_FORK) || defined(PROTO)
+#if defined(GUI_MAY_FORK) || defined(GUI_MAY_SPAWN) || defined(PROTO)
 /*
  * Return TRUE when there is any running job that we care about.
  */
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 509a31f0e6..e65ab94e38 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -4201,11 +4201,13 @@ f_foreground(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
 {
 #ifdef FEAT_GUI
     if (gui.in_use)
+    {
 	gui_mch_set_foreground();
-#else
-# ifdef MSWIN
+	return;
+    }
+#endif
+#if defined(MSWIN) && (!defined(FEAT_GUI) || defined(VIMDLL))
     win32_set_foreground();
-# endif
 #endif
 }
 
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 0ab5df6c0f..8766c66707 100644
--- a/