[WIN32] added a prepare-env script for jenkins to clean the environme…

…nt a little but keep the build deps.

tools/buildsteps/win32/prepare-env.bat

@@ -0,0 +1,20 @@
+@ECHO OFF
+
+ECHO Workspace is %WORKSPACE%
+
+rem git clean the untracked files but not the directories
+rem to keep the downloaded dependencies
+rem we assume git in path as this is a requirement
+
+cd %WORKSPACE%
+ECHO running git clean -xf
+git clean -xf
+
+rem cleaning additional directories
+ECHO delete build directories
+IF EXIST %WORKSPACE%\project\Win32BuildSetup\BUILD_WIN32 rmdir %WORKSPACE%\project\Win32BuildSetup\BUILD_WIN32 /S /Q
+IF EXIST %WORKSPACE%\project\Win32BuildSetup\dependencies rmdir %WORKSPACE%\project\Win32BuildSetup\dependencies /S /Q
+
+IF EXIST %WORKSPACE%\project\BuildDependencies\include rmdir %WORKSPACE%\project\BuildDependencies\include /S /Q
+IF EXIST %WORKSPACE%\project\BuildDependencies\lib rmdir %WORKSPACE%\project\BuildDependencies\lib /S /Q
+IF EXIST %WORKSPACE%\project\BuildDependencies\msys rmdir %WORKSPACE%\project\BuildDependencies\msys /S /Q