mesa: allow for extra per-context init
(cherry picked from commit 815cdcfbc0740c66b901361620c88d99541bdad2)
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index d6205fc..a41cb42 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -1234,6 +1234,10 @@
       ctx->FragmentProgram._MaintainTexEnvProgram = GL_TRUE;
    }
 
+#ifdef FEATURE_extra_context_init
+   _mesa_initialize_context_extra(ctx);
+#endif
+
    ctx->FirstTimeCurrent = GL_TRUE;
 
    return GL_TRUE;