MSYS2: Use date of last git commit instead of current date for packed filename

build_scripts/Windows-msys2/build/pack.bat

@@ -55,10 +55,11 @@ set RsVersion=%RsVersion.Major%.%RsVersion.Minor%.%RsVersion.Mini%
 :: Check WMIC is available
 wmic.exe alias /? >nul 2>&1 || echo WMIC is not available.&& goto error
 
-:: Use WMIC to retrieve date in format YYYYMMDD
-set RsDate=
-for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /format:list') do set RsDate=%%I
-set RsDate=%RsDate:~0,4%%RsDate:~4,2%%RsDate:~6,2%
+:: Get date
+call "%ToolsPath%\get-rs-date.bat" "%SourcePath%" RsDate
+if errorlevel 1 %cecho% error "Could not get date."& goto error
+
+if "%RsDate%"=="" %cecho% error "Could not get date."& goto error
 
 set QtMainVersion=%QtVersion:~0,1%
 set QtSharePath=%RsMinGWPath%\share\qt%QtMainVersion%\

build_scripts/Windows-msys2/tools/get-rs-date.bat

@@ -0,0 +1,32 @@
+REM Usage:
+REM call get-rs-date.bat SourcePath Variable
+
+setlocal
+
+set SourcePath=%~1
+set Variable=%~2
+if "%Variable%"=="" (
+	echo.
+	echo Parameter error
+	exit /B 1
+)
+
+:: Check git executable
+set GitPath=
+call "%~dp0find-in-path.bat" GitPath git.exe
+if "%GitPath%"=="" (
+	echo.
+	echo Git executable not found in PATH.
+	exit /B 1
+)
+
+set Date=
+
+pushd "%SourcePath%"
+rem This doesn't work: git log -1 --date=format:"%Y%m%d" --format="%ad"
+for /F "tokens=1,2,3* delims=-" %%A in ('git log -1 --date^=short --format^="%%ad"') do set Date=%%A%%B%%C
+popd
+
+:exit
+endlocal & set %Variable%=%Date%
+exit /B 0