build: Fix pywrap which wrongly includes config.gen.mk
build: Fix pywrap which wrongly includes config.gen.mk

That acutally breaks the build once config.mk is included in pre.mk
rather then post.mk.

gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim