pmt: revert 7f8090b

include/libgnulib/isnand-nolibm.h

@@ -1,45 +0,0 @@
-/* Test for NaN that does not need libm.
-   Copyright (C) 2007-2024 Free Software Foundation, Inc.
-
-   This file is free software: you can redistribute it and/or modify
-   it under the terms of the GNU Lesser General Public License as
-   published by the Free Software Foundation; either version 2.1 of the
-   License, or (at your option) any later version.
-
-   This file is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public License
-   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
-
-/* This file uses HAVE_ISNAND_IN_LIBC.  */
-#if !_GL_CONFIG_H_INCLUDED
- #error "Please include config.h first."
-#endif
-
-#if HAVE_ISNAND_IN_LIBC
-/* Get declaration of isnan macro.  */
-# include <math.h>
-# if (__GNUC__ >= 4) || (__clang_major__ >= 4)
-   /* GCC >= 4.0 and clang provide a type-generic built-in for isnan.  */
-#  undef isnand
-#  define isnand(x) __builtin_isnan ((double)(x))
-# else
-#  undef isnand
-#  define isnand(x) isnan ((double)(x))
-# endif
-#else
-/* Test whether X is a NaN.  */
-# undef isnand
-# define isnand rpl_isnand
-extern
-# ifdef __cplusplus
-"C"
-# endif
-int isnand (double x);
-#endif
-
-/* Tell <math.h> that our isnand does not need libm.  */
-#define HAVE_ISNAND_NOLIBM 1