[libcxx] [test] Detect the UCRT printf("%a") formatting bug (#99846)
This fixes testing with MinGW, if built without
__USE_MINGW_ANSI_STDIO=1.
On x86 MinGW, such a configuration fails printf tests with long doubles
due to mismatches between 80 and 64 bit long doubles - but on ARM,
there's no such issue, so building without __USE_MINGW_ANSI_STDIO=1 is
perfectly valid there.
Add another similar XFAIL to a libcxxabi test; this test isn't executed
in MSVC environments, so no XFAIL has been needed so far.
NOKEYCHECK=True
GitOrigin-RevId: ca69f515fe29fa98b7ab52e49c5b401bb22f64f6
diff --git a/test/test_demangle.pass.cpp b/test/test_demangle.pass.cpp
index fe55989..ab783cf 100644
--- a/test/test_demangle.pass.cpp
+++ b/test/test_demangle.pass.cpp
@@ -17,6 +17,8 @@
// 80-bit format, and this demangling test is failing on it.
// XFAIL: LIBCXX-ANDROID-FIXME && target={{i686|x86_64}}-{{.+}}-android{{.*}}
+// XFAIL: win32-broken-printf-a-precision
+
#include "support/timer.h"
#include <algorithm>
#include <cassert>
