Add new _mesa_lookup_parameter_constant() to search for a GLfloat4 constant
in a parameter list.
Use it in _mesa_add_named_constant() and _mesa_add_unnamed_constant() to
avoid duplication of identical constants.
diff --git a/src/mesa/shader/program.h b/src/mesa/shader/program.h
index 5095839..3f84ea8 100644
--- a/src/mesa/shader/program.h
+++ b/src/mesa/shader/program.h
@@ -249,19 +249,22 @@
                           const GLint *stateTokens);
 
 extern GLfloat *
-_mesa_lookup_parameter_value(struct gl_program_parameter_list *paramList,
+_mesa_lookup_parameter_value(const struct gl_program_parameter_list *paramList,
                              GLsizei nameLen, const char *name);
 
 extern GLint
-_mesa_lookup_parameter_index(struct gl_program_parameter_list *paramList,
+_mesa_lookup_parameter_index(const struct gl_program_parameter_list *paramList,
                              GLsizei nameLen, const char *name);
 
+extern GLboolean
+_mesa_lookup_parameter_constant(const struct gl_program_parameter_list *paramList,
+                                const GLfloat v[], GLsizei vSize,
+                                GLuint *posOut, GLuint *swizzleOut);
+
 extern void
 _mesa_load_state_parameters(GLcontext *ctx,
                             struct gl_program_parameter_list *paramList);
 
-
-
 extern void
 _mesa_print_instruction(const struct prog_instruction *inst);