Cmake: use ENV{VCPKG_ROOT}, fix msgfmt + minor.

Set VCPKG_DIR from ENV{VCPKG_ROOT} if set, otherwise set
ENV{VCPKG_ROOT}.
Set VCPKG_ARCH from VCPKG_TARGET_TRIPLET if set.
Fix check for VCPKG_ARCH being defined.
Describe options in comment at the top of the file.
Add build*/ out-of-source build dirs to toplevel .gitignore.
Change vcpkg_install.bat to use %VCPKG_ROOT% set by cmake or present in
the environment, and update/install only what's necessary.
Use Gettext.Tools from nuget on Windows for msgfmt.
Fix cmake linking script invocation by adding WORKING_DIRECTORY.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

.gitignore

@@ -245,3 +245,4 @@ Release/
 *.dSYM
 /contrib/buildsystems/out
 CMakeSettings.json
+build*/

compat/vcbuild/vcpkg_install.bat

@@ -40,38 +40,46 @@ REM ================================================================
 	@FOR /F "delims=" %%D IN ("%~dp0") DO @SET cwd=%%~fD
 	cd %cwd%
 
-	dir vcpkg\vcpkg.exe >nul 2>nul && GOTO :install_libraries
+	IF NOT DEFINED VCPKG_ROOT (
+		set VCPKG_ROOT=%cwd%\vcpkg
+	) ELSE (IF NOT EXIST %VCPKG_ROOT%\..\ (
+		echo Invalid VCPKG_ROOT: %VCPKG_ROOT%, not under a valid directory.
+		exit /B 1
+	))
+
+	IF EXIST %VCPKG_ROOT%\vcpkg.exe goto :install_libraries
 
 	git.exe version 2>nul
 	IF ERRORLEVEL 1 (
-	echo "***"
-	echo "Git not found. Please adjust your CMD path or Git install option."
-	echo "***"
-	EXIT /B 1 )
+		echo ***
+		echo Git not found. Please adjust your CMD path or Git install option.
+		echo ***
+		EXIT /B 1
+	)
 
-	echo Fetching vcpkg in %cwd%vcpkg
-	git.exe clone https://github.com/Microsoft/vcpkg vcpkg
+	echo Fetching vcpkg in %VCPKG_ROOT%
+	git.exe clone https://github.com/Microsoft/vcpkg %VCPKG_ROOT%
 	IF ERRORLEVEL 1 ( EXIT /B 1 )
 
-	cd vcpkg
+	cd %VCPKG_ROOT%
 	echo Building vcpkg
 	powershell -exec bypass scripts\bootstrap.ps1
 	IF ERRORLEVEL 1 ( EXIT /B 1 )
 
-	echo Successfully installed %cwd%vcpkg\vcpkg.exe
+	echo Successfully installed %VCPKG_ROOT%\vcpkg.exe
 
 :install_libraries
 
 	echo Installing third-party libraries(%arch%)...
 	FOR %%i IN (zlib expat libiconv openssl libssh2 curl) DO (
-	    cd %cwd%vcpkg
+	    cd %VCPKG_ROOT%
 	    IF NOT EXIST "packages\%%i_%arch%" CALL :sub__install_one %%i
 	    IF ERRORLEVEL 1 ( EXIT /B 1 )
 	)
 
 :install_defines
 	cd %cwd%
-	SET inst=%cwd%vcpkg\installed\%arch%
+	SET inst=%VCPKG_ROOT%\installed\%arch%
 
 	echo vcpkg_inc=-I"%inst%\include">VCPKG-DEFS
 	echo vcpkg_rel_lib=-L"%inst%\lib">>VCPKG-DEFS

contrib/buildsystems/CMakeLists.txt

@@ -44,8 +44,15 @@ This process generates a Makefile(Linux/*BSD/MacOS), Visual Studio solution(Wind
 Run `make` to build Git on Linux/*BSD/MacOS.
 Open git.sln on Windows and build Git.
 
-NOTE: By default CMake will install vcpkg locally to your source tree on configuration,
-to avoid this, add `-DNO_VCPKG=TRUE` to the command line when configuring.
+NOTE: By default CMake will install vcpkg locally to your source tree on
+configuration, to use your own VCPKG tree, set `$env:VCPKG_ROOT` to the
+path or pass `VCPKG_DIR`.
+
+To set the vcpkg arch (target triplet) pass `VCPKG_ARCH` e.g.:
+`-DVCPKG_ARCH=x64-windows`.
+
+To not use VCPKG, add `-DUSE_VCPKG=FALSE` to the command line when
+configuring.
 
 The Visual Studio default generator changed in v16.6 from its Visual Studio
 implemenation to `Ninja` This required changes to many CMake scripts.
@@ -67,7 +74,27 @@ if(NOT DEFINED CMAKE_EXPORT_COMPILE_COMMANDS)
 endif()
 
 if(USE_VCPKG)
-	set(VCPKG_DIR "${CMAKE_SOURCE_DIR}/compat/vcbuild/vcpkg")
+	if(NOT DEFINED VCPKG_DIR)
+		if(DEFINED ENV{VCPKG_ROOT})
+			set(VCPKG_DIR "$ENV{VCPKG_ROOT}")
+		else()
+			set(VCPKG_DIR "${CMAKE_SOURCE_DIR}/compat/vcbuild/vcpkg")
+		endif()
+
+		# Make sure ENV{VCPKG_ROOT} is set for vcpkg_install.bat
+		# and anything else that may need it.
+		set(ENV{VCPKG_ROOT} "${VCPKG_DIR}")
+	endif()
+
+	if(NOT DEFINED VCPKG_ARCH)
+		if(DEFINED VCPKG_TARGET_TRIPLET)
+			set(VCPKG_ARCH "${VCPKG_TARGET_TRIPLET}")
+		else()
+			message("VCPKG_ARCH: unset, using 'x64-windows'")
+			set(VCPKG_ARCH "x64-windows")
+		endif()
+	endif()
+
 	message("WIN32: ${WIN32}") # show its underlying text values
 	message("VCPKG_DIR: ${VCPKG_DIR}")
 	message("VCPKG_ARCH: ${VCPKG_ARCH}") # maybe unset
@@ -77,14 +104,8 @@ if(USE_VCPKG)
 	message("CMAKE_GENERATOR_PLATFORM: ${CMAKE_GENERATOR_PLATFORM}")
 	message("CMAKE_EXPORT_COMPILE_COMMANDS: ${CMAKE_EXPORT_COMPILE_COMMANDS}")
 	message("ENV(CMAKE_EXPORT_COMPILE_COMMANDS): $ENV{CMAKE_EXPORT_COMPILE_COMMANDS}")
-	if(NOT EXISTS ${VCPKG_DIR})
-		message("Initializing vcpkg and building the Git's dependencies (this will take a while...)")
-		execute_process(COMMAND ${CMAKE_SOURCE_DIR}/compat/vcbuild/vcpkg_install.bat ${VCPKG_ARCH})
-	endif()
-	if(NOT EXISTS ${VCPKG_ARCH})
-		message("VCPKG_ARCH: unset, using 'x64-windows'")
-		set(VCPKG_ARCH "x64-windows") # default from vcpkg_install.bat
-	endif()
+	message("Initializing vcpkg and building the Git's dependencies (this may take a while...)")
+	execute_process(COMMAND ${CMAKE_SOURCE_DIR}/compat/vcbuild/vcpkg_install.bat ${VCPKG_ARCH})
 	list(APPEND CMAKE_PREFIX_PATH "${VCPKG_DIR}/installed/${VCPKG_ARCH}")
 
 	# In the vcpkg edition, we need this to be able to link to libcurl
@@ -207,19 +228,50 @@ if(WIN32 AND NOT MSVC)#not required for visual studio builds
 	endif()
 endif()
 
-if(NO_GETTEXT)
-	message(STATUS "msgfmt not used under NO_GETTEXT")
-else()
+macro(get_nuget)
+	if(NOT EXISTS ${CMAKE_BINARY_DIR}/nuget.exe)
+		file(DOWNLOAD "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe" ${CMAKE_BINARY_DIR}/nuget.exe)
+	endif()
+
+	# Add nuget package source.
+	execute_process(
+		COMMAND nuget sources add -Name "NuGet official package source" -Source "https://api.nuget.org/v3/index.json"
+		WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+	)
+endmacro()
+
+macro(nuget_install pkg)
+    execute_process(
+	COMMAND nuget.exe install ${pkg} -OutputDirectory ${CMAKE_BINARY_DIR}/nuget
+	WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    )
+
+    # Find the path to the binaries in the package and add them to find path.
+    file(GLOB pkg_dir ${CMAKE_BINARY_DIR}/nuget/${pkg}*)
+
+    list(APPEND CMAKE_PROGRAM_PATH ${pkg_dir}/tools/bin)
+
+    set(CMAKE_PROGRAM_PATH "${CMAKE_PROGRAM_PATH}" CACHE STRING "External Program Search Path" FORCE)
+endmacro()
+
+find_program(msgfmt msgfmt)
+if(NOT msgfmt)
+	if(WIN32)
+		get_nuget()
+		nuget_install(Gettext.Tools)
+	endif()
+
 	find_program(MSGFMT_EXE msgfmt)
+
 	if(NOT MSGFMT_EXE)
-		if(USE_VCPKG)
-			set(MSGFMT_EXE ${CMAKE_SOURCE_DIR}/compat/vcbuild/vcpkg/downloads/tools/msys2/msys64/usr/bin/msgfmt.exe)
-		endif()
-		if(NOT EXISTS ${MSGFMT_EXE})
-			message(WARNING "Text Translations won't be built")
-			unset(MSGFMT_EXE)
-		endif()
+		message(WARNING "msgfmt not available and/or could not be installed, text translations won't be built.")
 	endif()
+else()
+	set(MSGFMT_EXE ${msgfmt})
+endif()
+
+if(MSGFMT_EXE)
+	set(MSGFMT_EXE ${MSGFMT_EXE} CACHE STRING "gettext msgfmt utility path" FORCE)
 endif()
 
 #Force all visual studio outputs to CMAKE_BINARY_DIR
@@ -813,7 +865,8 @@ endif()
 
 add_custom_command(OUTPUT ${git_links} ${git_http_links}
 		COMMAND ${CMAKE_COMMAND} -P ${CMAKE_BINARY_DIR}/CreateLinks.cmake
-		DEPENDS git git-remote-http)
+		DEPENDS git git-remote-http
+		WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
 add_custom_target(git-links ALL DEPENDS ${git_links} ${git_http_links})
 
 
@@ -1074,7 +1127,7 @@ file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "RUNTIME_PREFIX='${RUNTIME_PRE
 file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "NO_PYTHON='${NO_PYTHON}'\n")
 file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "SUPPORTS_SIMPLE_IPC='${SUPPORTS_SIMPLE_IPC}'\n")
 if(USE_VCPKG)
-	file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "PATH=\"$PATH:$TEST_DIRECTORY/../compat/vcbuild/vcpkg/installed/${VCPKG_ARCH}/bin\"\n")
+	file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "PATH=\"$PATH:${VCPKG_DIR}/installed/${VCPKG_ARCH}/bin\"\n")
 endif()
 
 #Make the tests work when building out of the source tree