diff -ruNp mozilla.orig/toolkit/mozapps/installer/packager.py mozilla/toolkit/mozapps/installer/packager.py
--- mozilla.orig/toolkit/mozapps/installer/packager.py	2015-04-03 04:30:06.000000000 +0200
+++ mozilla/toolkit/mozapps/installer/packager.py	2015-04-10 14:52:45.133163567 +0200
@@ -152,7 +152,7 @@ def precompile_cache(formatter, source_p
     os.remove(cache)
 
     try:
-        extra_env = {'MOZ_STARTUP_CACHE': cache}
+        extra_env = {'MOZ_STARTUP_CACHE': cache, 'LD_PRELOAD': os.path.join(gre_path, 'libxul.so')}
         if buildconfig.substs.get('MOZ_TSAN'):
             extra_env['TSAN_OPTIONS'] = 'report_bugs=0'
         if launcher.launch(['xpcshell', '-g', gre_path, '-a', app_path,