wassert replacement without forbidden MessageBoxW

git-svn-id: https://mingw-w64.svn.sourceforge.net/svnroot/mingw-w64/trunk@5869 4407c894-4637-0410-b4f5-ada5f102cad1
GetModuleHandle replacement

git-svn-id: https://mingw-w64.svn.sourceforge.net/svnroot/mingw-w64/trunk@5870 4407c894-4637-0410-b4f5-ada5f102cad1