[libc++] Temporarily disable an availability test that is broken

The current lit test suite doesn't really allow us to express that the
test should be disabled when testing the trunk variant of libc++, even
if we're running it on a supported macOS. Because of that, the test
is enabled when _LIBCPP_DISABLE_AVAILABILITY is defined, and the test
XPASSes.

diff --git a/libcxx/test/libcxx/utilities/charconv/charconv.to.chars/availability.fail.cpp b/libcxx/test/libcxx/utilities/charconv/charconv.to.chars/availability.fail.cpp
index b1898e1..2aff214 100644 (file)
--- a/libcxx/test/libcxx/utilities/charconv/charconv.to.chars/availability.fail.cpp
+++ b/libcxx/test/libcxx/utilities/charconv/charconv.to.chars/availability.fail.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: c++98, c++03
 // REQUIRES: availability=macosx10.7 || availability=macosx10.8 || availability=macosx10.9 || availability=macosx10.10 || availability=macosx10.11 || availability=macosx10.12 || availability=macosx10.13 || availability=macosx10.14
 
+// TODO(ldionne): This test is currently broken when testing libc++ trunk on one of the above macOS's
+// UNSUPPORTED: macosx
+
 // Test the availability markup on std::to_chars.
 
 #include <charconv>