Add support for builtin deprecated fs varyings.

Fixes glsl-color.frag.
diff --git a/ir_variable.cpp b/ir_variable.cpp
index 9344170..df8e4c3 100644
--- a/ir_variable.cpp
+++ b/ir_variable.cpp
@@ -136,6 +136,14 @@
 			   instructions, symtab);
    }
 
+   /* FINISHME: Add support for gl_TexCoord[] */
+   for (unsigned i = 0
+	   ; i < Elements(builtin_110_deprecated_fs_variables)
+	   ; i++) {
+      add_builtin_variable(& builtin_110_deprecated_fs_variables[i],
+			   instructions, symtab);
+   }
+
    /* FINISHME: Add support for gl_FragData[GL_MAX_DRAW_BUFFERS]. */
 }