Fixed compiler error on Mac OS X in with the atomic functions

git-svn-id: https://angelscript.svn.sourceforge.net/svnroot/angelscript/trunk@1546 404ce1b2-830e-0410-a2e2-b09542c77caf
Fixed segfault in GetGlobalVarIndexByDecl on passing invalid declaration

git-svn-id: https://angelscript.svn.sourceforge.net/svnroot/angelscript/trunk@1547 404ce1b2-830e-0410-a2e2-b09542c77caf