Building a testdir on macOS 12.5, I also see this error:
In file included from ../../gltests/test-math-c++2.cc:20:
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1/cmath:572:12:
error: reference to unresolved using declaration
return isnan(__lcpp_x);
^
../gllib/math.h:3138:19: note: expanded from macro 'isnan'
# define isnan rpl_isnan
^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1/cmath:325:1:
note: using declaration annotated with 'using_if_exists' here
using ::isnan _LIBCPP_USING_IF_EXISTS;
^
1 error generated.
make[4]: *** [test-math-c++2.o] Error 1
Apparently the patch I did on 2021-03-20 for macOS 11.2 (__clang_major__ = 12)
needs to reverted for macOS 12.5 (__clang_major__ = 14). Oh well.
2023-02-09 Bruno Haible <[email protected]>
math: Fix compilation error in C++ mode on macOS 12.5.
* lib/math.in.h (isnan): On macOS, treat clang version 14 again like
clang versions < 12.
diff --git a/lib/math.in.h b/lib/math.in.h
index 70b75e2399..76d48a4443 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2624,7 +2624,7 @@ _GL_EXTERN_C int rpl_isnanl (long double x)
_GL_ATTRIBUTE_CONST;
# if defined isnan || defined GNULIB_NAMESPACE
_GL_MATH_CXX_REAL_FLOATING_DECL_1 (isnan)
# undef isnan
-# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined
__MACH__ && __clang_major__ < 12) || (defined __FreeBSD__ && (__clang_major__ <
7 || __clang_major__ >= 11)) || defined __OpenBSD__ || (defined _WIN32 &&
!defined __CYGWIN__)))
+# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined
__MACH__ && __clang_major__ != 12) || (defined __FreeBSD__ && (__clang_major__
< 7 || __clang_major__ >= 11)) || defined __OpenBSD__ || (defined _WIN32 &&
!defined __CYGWIN__)))
/* This platform's <cmath> possibly defines isnan through a set of inline
functions. */
_GL_MATH_CXX_REAL_FLOATING_DECL_2 (isnan, rpl_isnan, bool)
