Compiling on Windows with "scons statetrackers=mesa drivers=softpipe winsys=gdi" failed when it tried to run compile.exe:

C:\Documents and Settings\[...]\mesa\build\windows-x86-debug-glsl\compile.exe fragment src\mesa\slang\library\slang_common_builtin.gc src\mesa\slang\library\slang_common_builtin_gc.h
'C:\Documents' is not recognized as an internal or external command, operable program or batch file.
scons: *** [src\mesa\slang\library\slang_common_builtin_gc.h] Error 1
scons: building terminated because of errors.

The problem looks like it starts in library/SConscript:

bld_frag = Builder(
	action = Action(glsl_compile[0].abspath + ' fragment $SOURCE $TARGET', '$CODEGENCODESTR'),
	emitter = glsl_compile_emitter,
	suffix = '.gc',
	src_suffix = '_gc.h')