XFAIL __cxa_uncaught_exception() test

Author: ldionne

libcxxabi/test/uncaught_exception.pass.cpp

@@ -11,6 +11,13 @@
 // This tests that libc++abi still provides __cxa_uncaught_exception() for
 // ABI compatibility, even though the Standard doesn't require it to.
 
+// __cxa_uncaught_exception was not re-exported from libc++ previously. This leads
+// to undefined symbols when linking against a libc++ that re-exports the symbols,
+// but running against a libc++ that doesn't. Fortunately, usage of __cxa_uncaught_exception()
+// in the wild seems to be close to non-existent.
+// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14}}
+// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx{{11|12|13|14}}
+
 #include <cxxabi.h>
 #include <cassert>