ubuntu-buildroot/output/build/host-bison-3.8.2/m4/ffs.m4

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# ffs.m4 serial 5
dnl Copyright (C) 2011-2021 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_FFS],
[
AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
dnl We can't use AC_CHECK_FUNC here, because ffs() is defined as a
dnl static inline function when compiling for Android 4.2 or older.
dnl But require that ffs() is declared; otherwise we may be using
dnl the GCC built-in function, which leads to warnings
dnl "warning: implicit declaration of function 'ffs'".
AC_CACHE_CHECK([for ffs], [gl_cv_func_ffs],
[AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <strings.h>
int x;
]],
[[int (*func) (int) = ffs;
return func (x);
]])
],
[gl_cv_func_ffs=yes],
[gl_cv_func_ffs=no])
])
if test $gl_cv_func_ffs = no; then
HAVE_FFS=0
fi
])