X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Flog2f.m4;h=89da2311208456587546e0b33a18c7434521b1ba;hb=5191b3546cfb6c163228c23f214e325ddf60d46f;hp=d9fffd0aaa1fb3a1eb20968c635c8efa9b6f0e38;hpb=3c7a0ee522192719470c8836a964fc6175fa6c96;p=gnulib.git

diff --git a/m4/log2f.m4 b/m4/log2f.m4
index d9fffd0aa..89da23112 100644
--- a/m4/log2f.m4
+++ b/m4/log2f.m4
@@ -1,5 +1,5 @@
-# log2f.m4 serial 2
-dnl Copyright (C) 2010-2012 Free Software Foundation, Inc.
+# log2f.m4 serial 3
+dnl Copyright (C) 2010-2013 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.
@@ -38,6 +38,7 @@ AC_DEFUN([gl_FUNC_LOG2F],
 
     m4_ifdef([gl_FUNC_LOG2F_IEEE], [
       if test $gl_log2f_required = ieee && test $REPLACE_LOG2F = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
         AC_CACHE_CHECK([whether log2f works according to ISO C 99 with IEC 60559],
           [gl_cv_func_log2f_ieee],
           [
@@ -78,7 +79,13 @@ int main (int argc, char *argv[])
               ]])],
               [gl_cv_func_log2f_ieee=yes],
               [gl_cv_func_log2f_ieee=no],
-              [gl_cv_func_log2f_ieee="guessing no"])
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_log2f_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_log2f_ieee="guessing no" ;;
+               esac
+              ])
             LIBS="$save_LIBS"
           ])
         case "$gl_cv_func_log2f_ieee" in