1. According to this page, https://developer.mozilla.org/en-US/docs/SpiderMonkey/JSAPI_Reference/JS_ConstructObject
The JS_ConstructObject method you use in src/scenegraph/vrml_smjs.c and some other places are obsoleted.
Mozilla suggests to use "JS_New" to replace them.
Even if you don't replace it, current code can't be built either, because new JS_ConstructObject has four parameters, but our code only give the first three of them, thus will cause a "too few arguments" error.
2. the "int switch_up" in applications/osmozilla/nsIOsmozilla.idl is werid...because Mozilla doesn't have this type, actually it suggests to use "long"
You can see it here: https://developer.mozilla.org/en-US/docs/XPIDL
Those two bugs make gpac-0.5.0 and svn4178 both can't be compiled against libmozjs185 and xulrunner-15.
That's the version openSUSE 12.2, Ubuntu 12.10, ArchLinux uses unluckily....