Rubber-stamped by Holger Freyther.

        Do not enable RTTI or exceptions in debug builds, matching release
        builds. They don't help much with debugging and significantly slow
        down and increase the size of the debug build.

        * GNUmakefile.am:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@38072 268f45cc-cd09-0410-ab3c-d52691b4dbfc