[gjs] jsapi-util: Fix JS::GCPolicy definition with namespace

[Philip Chimento <pchimento src gnome org>]

commit 5ee6593cec32068ed6faedb62220afac29ced4ac
Author: Philip Chimento <philip chimento gmail com>
Date:   Fri Jun 1 13:35:38 2018 -0700

    jsapi-util: Fix JS::GCPolicy definition with namespace
    
    Apparently GCC 5.x doesn't like this, so we have to explicitly put this
    template specialization into a namespace JS {} block. I caught the one
    for GCPolicy<ParamRef> in a previous commit, but forgot about this one.
    
    Unreviewed, pushing to fix build.

 gjs/jsapi-util.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/gjs/jsapi-util.h b/gjs/jsapi-util.h
index 5b12a8ee..7bb3e5a6 100644
--- a/gjs/jsapi-util.h
+++ b/gjs/jsapi-util.h
@@ -77,8 +77,10 @@ public:
 };
 
 /* For use of GjsAutoInfo<T> in GC hash maps */
+namespace JS {
 template<typename T>
-struct JS::GCPolicy<GjsAutoInfo<T>> : public JS::IgnoreGCPolicy<GjsAutoInfo<T>> {};
+struct GCPolicy<GjsAutoInfo<T>> : public IgnoreGCPolicy<GjsAutoInfo<T>> {};
+}
 
 struct GjsJSFreeArgs {
     void operator() (char *str) {