[platform-releng-dev] ignore compiler warnings in recent builds

[Markus Keller <markus_keller@xxxxxxxxxx>]

Recent builds contain quite a few compiler warnings about resource leaks. 
You can disregard them for now, and we will disable them for M4.

Background:
Some of the warnings are valid, but many are false positives (not real 
problems, since the resource is e.g. only a StringReader that doesn't hold 
on to OS resources). See also https://bugs.eclipse.org/365566

Markus