X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fcopysignl.m4;h=702a81a474f03a510e9b2f0222b9be2de288e18e;hb=533101a268dc5015a140ff4695d8eeb04fbe57b6;hp=80c7b18af4738efb3ddd32afd8a871bc22777511;hpb=472322ae1a1ca95df1cc9b80031348e04fc5b6bc;p=gnulib.git

diff --git a/m4/copysignl.m4 b/m4/copysignl.m4
index 80c7b18af..702a81a47 100644
--- a/m4/copysignl.m4
+++ b/m4/copysignl.m4
@@ -1,5 +1,5 @@
-# copysignl.m4 serial 2
-dnl Copyright (C) 2011 Free Software Foundation, Inc.
+# copysignl.m4 serial 3
+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.
@@ -9,6 +9,9 @@ AC_DEFUN([gl_FUNC_COPYSIGNL],
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
 
+  dnl Persuade glibc <math.h> to declare copysignl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Determine COPYSIGNL_LIBM.
   gl_MATHFUNC([copysignl], [long double], [(long double, long double)])
   if test $gl_cv_func_copysignl_no_libm = no \