Adding MS_CURRENT besides MS_BASE in the Windows builds

[tamas]

In order to add the mapscript python build steps to the buildbot we should separate the mapserver build directory and the base directory for the libraries. I would suggest adding MS_CURRENT as:

!IFNDEF MS_CURRENT MS_CURRENT = $(MS_BASE) !ENDIF

And mapscriptvars would use MS_CURRENT instead of MS_BASE like:

mapscriptvars: makefile.vc nmake.opt

-del mapscriptvars echo $(MS_CURRENT) > mapscriptvars echo $(MS_DEFS) -DWIN32 -D_WIN32 >> mapscriptvars echo $(INCLUDES) >> mapscriptvars echo $(LIBS_DLL) >> mapscriptvars echo $(LIBS) >> mapscriptvars findstr MS_VERSION mapserver.h | findstr define >> mapscriptvars

[tamas]

Applied in the trunk