I'm reverting one of the changes made to exception.cpp in r151717. I'm unsure what the change was trying to do, but it didn't do the right thing for __APPLE__. So instead of trying to guess what was intended, I'm just putting it back the way it was.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@151727 91177308-0d34-0410-b5e6-96231b3b80d8

src/exception.cpp

@@ -99,6 +99,10 @@ bool uncaught_exception() _NOEXCEPT
 #if __APPLE__
     // on Darwin, there is a helper function so __cxa_get_globals is private
     return __cxa_uncaught_exception();
+#elif LIBCXXRT
+    __cxa_eh_globals * globals = __cxa_get_globals();
+    return (globals->uncaughtExceptions != 0);
+#else  // __APPLE__
     #warning uncaught_exception not yet implemented
     ::abort();
 #endif  // __APPLE__