mesa/glsl: rename preprocess to glcpp_preprocess

This symbol with dricore escapes into the namespace, its too generic,
we should prefix it with something just to be nice.

Should be applied to stable + 9.0

Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/glsl/glcpp/pp.c

@@ -150,7 +150,7 @@ remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
 }
 
 int
-preprocess(void *ralloc_ctx, const char **shader, char **info_log,
+glcpp_preprocess(void *ralloc_ctx, const char **shader, char **info_log,
 	   const struct gl_extensions *extensions, int api)
 {
 	int errors;