Proposed workaround/fix for:
https://bugzilla.mozilla.org/show_bug.cgi?id=1426865

diff --git a/js/public/TypeDecls.h b/js/public/TypeDecls.h
index acb93f9..cbd4b04 100644
--- js/public/TypeDecls.h
+++ js/public/TypeDecls.h
@@ -22,6 +22,8 @@
 
 #include "js-config.h"
 
+#pragma GCC visibility push(default)
+
 struct JSContext;
 class JSFunction;
 class JSObject;
@@ -76,4 +78,6 @@ typedef PersistentRooted<Value>       PersistentRootedValue;
 
 } // namespace JS
 
+#pragma GCC visibility pop
+
 #endif /* js_TypeDecls_h */