svga: specify include path for git_sha1.h for out-of-src builds
svga: specify include path for git_sha1.h for out-of-src builds

If we're doing an out-of-src build, we need to specify the #include
patch to find git_sha1.h

Reviewed-by: Charmaine Lee <67ce69700661ea856134ddb10419a330e5f037d7@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler