glsl: Fix use of uninitialized values in _mesa_glsl_parse_state ctor.

This has probably existed since e5e34ab18e or so.

NOTE: This is a candidate for the 7.9 and 7.10 branches.

src/glsl/builtins/tools/generate_builtins.py

@@ -152,6 +152,8 @@ read_builtins(GLenum target, const char *protos, const char **functions, unsigne
 {
    struct gl_context fakeCtx;
    fakeCtx.API = API_OPENGL;
+   fakeCtx.Const.GLSLVersion = 130;
+   fakeCtx.Extensions.ARB_ES2_compatibility = true;
    gl_shader *sh = _mesa_new_shader(NULL, 0, target);
    struct _mesa_glsl_parse_state *st =
       new(sh) _mesa_glsl_parse_state(&fakeCtx, target, sh);