glsl: process blend_support_* qualifiers

v2 (Ken): Add a BLEND_NONE enum value (no qualifiers in use).
v3 (Ken): Rename gl_blend_support_qualifier to gl_advanced_blend_mode.
v4 (Ken): Mark map[] as static const (Ilia).

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>

src/compiler/glsl/ast.h

@@ -596,6 +596,11 @@ struct ast_type_qualifier {
          unsigned subroutine:1;  /**< Is this marked 'subroutine' */
          unsigned subroutine_def:1; /**< Is this marked 'subroutine' with a list of types */
 	 /** \} */
+
+         /** \name Qualifiers for GL_KHR_blend_equation_advanced */
+         /** \{ */
+         unsigned blend_support:1; /**< Are there any blend_support_ qualifiers */
+         /** \} */
       }
       /** \brief Set of flags, accessed by name. */
       q;