X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ftruncf.m4;h=e7a2c72c3015c7b2ec30bf75216d04aa69d39ef1;hb=1276a2c5f24c0c932426aca9c899fa524d2443f2;hp=f917de584a0dc262ccb595754a2dceb307013a16;hpb=d60f3b0c6b0f93a601acd1cfd3923f94ca05abb0;p=gnulib.git

diff --git a/m4/truncf.m4 b/m4/truncf.m4
index f917de584..e7a2c72c3 100644
--- a/m4/truncf.m4
+++ b/m4/truncf.m4
@@ -1,5 +1,5 @@
-# truncf.m4 serial 4
-dnl Copyright (C) 2007, 2010-2011 Free Software Foundation, Inc.
+# truncf.m4 serial 9
+dnl Copyright (C) 2007, 2010-2014 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.
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_TRUNCF],
   dnl Persuade glibc <math.h> to declare truncf().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   dnl Test whether truncf() is declared.
-  AC_CHECK_DECLS([truncf], , , [#include <math.h>])
+  AC_CHECK_DECLS([truncf], , , [[#include <math.h>]])
   if test "$ac_cv_have_decl_truncf" = yes; then
     dnl Test whether truncf() can be used without libm.
     TRUNCF_LIBM=?
@@ -43,6 +43,7 @@ AC_DEFUN([gl_FUNC_TRUNCF],
     fi
     m4_ifdef([gl_FUNC_TRUNCF_IEEE], [
       if test $gl_truncf_required = ieee && test $REPLACE_TRUNCF = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
         AC_CACHE_CHECK([whether truncf works according to ISO C 99 with IEC 60559],
           [gl_cv_func_truncf_ieee],
           [
@@ -56,17 +57,25 @@ AC_DEFUN([gl_FUNC_TRUNCF],
 #include <math.h>
 ]gl_FLOAT_MINUS_ZERO_CODE[
 ]gl_FLOAT_SIGNBIT_CODE[
-int main()
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
 {
+  float (*my_truncf) (float) = argc ? truncf : dummy;
   /* Test whether truncf (-0.0f) is -0.0f.  */
-  if (signbitf (minus_zerof) && !signbitf (truncf (minus_zerof)))
+  if (signbitf (minus_zerof) && !signbitf (my_truncf (minus_zerof)))
     return 1;
   return 0;
 }
               ]])],
               [gl_cv_func_truncf_ieee=yes],
               [gl_cv_func_truncf_ieee=no],
-              [gl_cv_func_truncf_ieee="guessing no"])
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_truncf_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_truncf_ieee="guessing no" ;;
+               esac
+              ])
             LIBS="$save_LIBS"
           ])
         case "$gl_cv_func_truncf_ieee" in
@@ -79,7 +88,7 @@ int main()
     HAVE_DECL_TRUNCF=0
   fi
   if test $HAVE_DECL_TRUNCF = 0 || test $REPLACE_TRUNCF = 1; then
-    AC_LIBOBJ([truncf])
+    dnl No libraries are needed to link lib/truncf.c.
     TRUNCF_LIBM=
   fi
   AC_SUBST([TRUNCF_LIBM])