--- /dev/null
+# copysign.m4 serial 1
+dnl Copyright (C) 2011-2013 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_COPYSIGN],
+[
+ AC_REQUIRE([gl_MATH_H_DEFAULTS])
+
+ dnl Determine COPYSIGN_LIBM.
+ gl_MATHFUNC([copysign], [double], [(double, double)])
+ if test $gl_cv_func_copysign_no_libm = no \
+ && test $gl_cv_func_copysign_in_libm = no; then
+ HAVE_COPYSIGN=0
+ COPYSIGN_LIBM=
+ fi
+ AC_SUBST([COPYSIGN_LIBM])
+])