nir: forward-declare 'struct gl_shader_program'

Drop extra #include which is otherwise unneeded (and makes this header
difficult to include from outside of src/mesa).

Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/nir/glsl_to_nir.h

@@ -26,12 +26,13 @@
  */
 
 #include "nir.h"
-#include "compiler/glsl/glsl_parser_extras.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+struct gl_shader_program;
+
 nir_shader *glsl_to_nir(const struct gl_shader_program *shader_prog,
                         gl_shader_stage stage,
                         const nir_shader_compiler_options *options);