-# fmodf.m4 serial 2
+# fmodf.m4 serial 3
dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_FUNC_FMOD])
+ dnl Persuade glibc <math.h> to declare fmodf().
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
dnl Test whether fmodf() exists. Assume that fmodf(), if it exists, is
dnl defined in the same library as fmod().
save_LIBS="$LIBS"