Bug 784858: Pass LD_PRELOAD to child processes. r=cjones

ipc/glue/GeckoChildProcessHost.cpp

@@ -535,6 +535,12 @@ GeckoChildProcessHost::PerformAsyncLaunchInternal(std::vector<std::string>& aExt
   }
 #endif  // ANDROID
 
+#ifdef MOZ_WIDGET_GONK
+  if (const char *ldPreloadPath = getenv("LD_PRELOAD")) {
+    newEnvVars["LD_PRELOAD"] = ldPreloadPath;
+  }
+#endif // MOZ_WIDGET_GONK
+
   // remap the IPC socket fd to a well-known int, as the OS does for
   // STDOUT_FILENO, for example
   int srcChannelFd, dstChannelFd;