math: Ensure declarations of math functions.

[gnulib.git] / m4 / fmal.m4

diff --git a/m4/fmal.m4 b/m4/fmal.m4
index eb37971..3a5aba2 100644 (file)
--- a/m4/fmal.m4
+++ b/m4/fmal.m4
@@ -1,4 +1,4 @@
-# fmal.m4 serial 1
+# fmal.m4 serial 2
 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,
@@ -9,6 +9,9 @@ AC_DEFUN([gl_FUNC_FMAL],
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
 
+  dnl Persuade glibc <math.h> to declare fmal().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Determine FMAL_LIBM.
   gl_MATHFUNC([fmal], [long double], [(long double, long double, long double)])
   if test $gl_cv_func_fmal_no_libm = yes \