vcbuild: install ARM64 dependencies when building ARM64 binaries

Co-authored-by: Dennis Ameling <dennis@dennisameling.com>
Signed-off-by: Ian Bearman <ianb@microsoft.com>
Signed-off-by: Dennis Ameling <dennis@dennisameling.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

compat/vcbuild/README

@@ -6,7 +6,11 @@ The Steps to Build Git with VS2015 or VS2017 from the command line.
    Prompt or from an SDK bash window:
 
    $ cd <repo_root>
-   $ ./compat/vcbuild/vcpkg_install.bat
+   $ ./compat/vcbuild/vcpkg_install.bat x64-windows
+
+   or
+
+   $ ./compat/vcbuild/vcpkg_install.bat arm64-windows
 
    The vcpkg tools and all of the third-party sources will be installed
    in this folder:

compat/vcbuild/vcpkg_copy_dlls.bat

@@ -15,7 +15,12 @@ REM ================================================================
 	@FOR /F "delims=" %%D IN ("%~dp0") DO @SET cwd=%%~fD
 	cd %cwd%
 
-	SET arch=x64-windows
+	SET arch=%2
+	IF NOT DEFINED arch (
+		echo defaulting to 'x64-windows`. Invoke %0 with 'x86-windows', 'x64-windows', or 'arm64-windows'
+		set arch=x64-windows
+	)
+
 	SET inst=%cwd%vcpkg\installed\%arch%
 
 	IF [%1]==[release] (

compat/vcbuild/vcpkg_install.bat

@@ -31,6 +31,12 @@ REM ================================================================
 
 	SETLOCAL EnableDelayedExpansion
 
+	SET arch=%1
+	IF NOT DEFINED arch (
+		echo defaulting to 'x64-windows`. Invoke %0 with 'x86-windows', 'x64-windows', or 'arm64-windows'
+		set arch=x64-windows
+	)
+
 	@FOR /F "delims=" %%D IN ("%~dp0") DO @SET cwd=%%~fD
 	cd %cwd%
 
@@ -55,9 +61,8 @@ REM ================================================================
 	echo Successfully installed %cwd%vcpkg\vcpkg.exe
 
 :install_libraries
-	SET arch=x64-windows
 
-	echo Installing third-party libraries...
+	echo Installing third-party libraries(%arch%)...
 	FOR %%i IN (zlib expat libiconv openssl libssh2 curl) DO (
 	    cd %cwd%vcpkg
 	    IF NOT EXIST "packages\%%i_%arch%" CALL :sub__install_one %%i

contrib/buildsystems/Generators/Vcxproj.pm

@@ -193,7 +193,7 @@ EOM
     <PreBuildEvent Condition="!Exists('$cdup\\compat\\vcbuild\\vcpkg\\installed\\\$(VCPKGArch)\\include\\openssl\\ssl.h')">
       <Message>Initialize VCPKG</Message>
       <Command>del "$cdup\\compat\\vcbuild\\vcpkg"</Command>
-      <Command>call "$cdup\\compat\\vcbuild\\vcpkg_install.bat"</Command>
+      <Command>call "$cdup\\compat\\vcbuild\\vcpkg_install.bat" \$(VCPKGArch)</Command>
     </PreBuildEvent>
 EOM
     }