libstdc++: Work around clang misdesign in time_get<>::get [PR104990]

Apparently clang has a -fgnuc-version= option which allows it to pretend
it is any GCC version the user likes.  It is already bad that it claims to
be GCC 4.2 compatible by default when it is not (various unimplemented
extensions at least), but this option is a horrible idea.

Anyway, this patch adds a hack for it.

2022-03-21  Jakub Jelinek  <jakub@redhat.com>

	PR libstdc++/104990
	* include/bits/locale_facets_nonio.tcc (get): Don't check if do_get
	isn't overloaded if __clang__ is defined.

diff --git a/libstdc++-v3/include/bits/locale_facets_nonio.tcc b/libstdc++-v3/include/bits/locale_facets_nonio.tcc
index 8c37a70..17a2c8d 100644 (file)
--- a/libstdc++-v3/include/bits/locale_facets_nonio.tcc
+++ b/libstdc++-v3/include/bits/locale_facets_nonio.tcc
@@ -1465,7 +1465,7 @@ _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
       ctype<_CharT> const& __ctype = use_facet<ctype<_CharT> >(__loc);
       __err = ios_base::goodbit;
       bool __use_state = false;
-#if __GNUC__ >= 5
+#if __GNUC__ >= 5 && !defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wpmf-conversions"
       // Nasty hack.  The C++ standard mandates that get invokes the do_get