X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fmodfl.m4;h=a7e1475737a7e2f33e44008ea04326a70cb21806;hb=23eecb48e39afd0d267d64d40ba6bf97aa865e13;hp=7764eb226a636e7427a8879e6949ff8ded8645f9;hpb=579928caf1c6bb983cbba7ee18603c077be78392;p=gnulib.git

diff --git a/m4/modfl.m4 b/m4/modfl.m4
index 7764eb226..a7e147573 100644
--- a/m4/modfl.m4
+++ b/m4/modfl.m4
@@ -1,5 +1,5 @@
-# modfl.m4 serial 1
-dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
+# modfl.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.
@@ -10,14 +10,19 @@ AC_DEFUN([gl_FUNC_MODFL],
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
 
+  dnl Persuade glibc <math.h> to declare modfl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Test whether modfl() exists. We cannot assume that modfl(), if it
   dnl exists, is defined in the same library as modf(). This is not the case
   dnl on FreeBSD, Solaris.
   gl_MATHFUNC([modfl], [long double], [(long double, long double *)])
   if test $gl_cv_func_modfl_no_libm = yes \
      || test $gl_cv_func_modfl_in_libm = yes; then
+    :
     m4_ifdef([gl_FUNC_MODFL_IEEE], [
       if test $gl_modfl_required = ieee && test $REPLACE_MODFL = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
         AC_CACHE_CHECK([whether modfl works according to ISO C 99 with IEC 60559],
           [gl_cv_func_modfl_ieee],
           [
@@ -57,7 +62,13 @@ int main (int argc, char *argv[])
               ]])],
               [gl_cv_func_modfl_ieee=yes],
               [gl_cv_func_modfl_ieee=no],
-              [gl_cv_func_modfl_ieee="guessing no"])
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_modfl_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_modfl_ieee="guessing no" ;;
+               esac
+              ])
             LIBS="$save_LIBS"
           ])
         case "$gl_cv_func_modfl_ieee" in