mesa: implement glGetUniformiv() with new ctx->Driver function

The old implementation could overwrite the caller's param buffer.

src/mesa/main/shaders.c

@@ -128,6 +128,7 @@ _mesa_DeleteObjectARB(GLhandleARB obj)
 void GLAPIENTRY
 _mesa_DeleteProgram(GLuint name)
 {
+   printf("%s name=%u\n", __FUNCTION__, name);
    if (name) {
       GET_CURRENT_CONTEXT(ctx);
       ctx->Driver.DeleteProgram2(ctx, name);