Merge commit 'a39d4083cab589d7cd6a13e8a4b8db8875261d75'

[gnulib.git] / m4 / ldexpl.m4

diff --git a/m4/ldexpl.m4 b/m4/ldexpl.m4
index 4e419cf..6959f42 100644 (file)
--- a/m4/ldexpl.m4
+++ b/m4/ldexpl.m4
@@ -1,5 +1,5 @@
-# ldexpl.m4 serial 13
-dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
+# ldexpl.m4 serial 16
+dnl Copyright (C) 2007-2014 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.
@@ -7,10 +7,16 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_LDEXPL],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
   AC_REQUIRE([gl_FUNC_ISNANL]) dnl for ISNANL_LIBM
+
+  dnl Persuade glibc <math.h> to declare ldexpl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Check whether it's declared.
-  dnl MacOS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
+  dnl Mac OS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
   AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [[#include <math.h>]])
+
   LDEXPL_LIBM=
   if test $HAVE_DECL_LDEXPL = 1; then
     gl_CHECK_LDEXPL_NO_LIBM
@@ -53,7 +59,12 @@ AC_DEFUN([gl_FUNC_LDEXPL],
   fi
   if test $HAVE_DECL_LDEXPL = 0 || test $gl_func_ldexpl = no; then
     dnl Find libraries needed to link lib/ldexpl.c.
-    LDEXPL_LIBM="$ISNANL_LIBM"
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_LDEXP])
+      LDEXPL_LIBM="$LDEXP_LIBM"
+    else
+      LDEXPL_LIBM="$ISNANL_LIBM"
+    fi
   fi
   AC_SUBST([LDEXPL_LIBM])
 ])
@@ -76,7 +87,7 @@ AC_DEFUN([gl_CHECK_LDEXPL_NO_LIBM],
 ])
 
 dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1
-dnl and MacOS X 10.4/PowerPC).
+dnl and Mac OS X 10.4/PowerPC).
 AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])