Avoid "guessing no" guesses when cross-compiling to glibc systems.

[gnulib.git] / m4 / log1pl.m4

diff --git a/m4/log1pl.m4 b/m4/log1pl.m4
index 5a72299..cd4f667 100644 (file)
--- a/m4/log1pl.m4
+++ b/m4/log1pl.m4
@@ -1,4 +1,4 @@
-# log1pl.m4 serial 2
+# log1pl.m4 serial 3
 dnl Copyright (C) 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,
@@ -24,6 +24,7 @@ AC_DEFUN([gl_FUNC_LOG1PL],
     LOG1PL_LIBM="$LOG1P_LIBM"
     m4_ifdef([gl_FUNC_LOG1PL_IEEE], [
       if test $gl_log1pl_required = ieee && test $REPLACE_LOG1PL = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
         AC_CACHE_CHECK([whether log1pl works according to ISO C 99 with IEC 60559],
           [gl_cv_func_log1pl_ieee],
           [
@@ -50,7 +51,13 @@ int main (int argc, char *argv[])
               ]])],
               [gl_cv_func_log1pl_ieee=yes],
               [gl_cv_func_log1pl_ieee=no],
-              [gl_cv_func_log1pl_ieee="guessing no"])
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_log1pl_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_log1pl_ieee="guessing no" ;;
+               esac
+              ])
             LIBS="$save_LIBS"
           ])
         case "$gl_cv_func_log1pl_ieee" in