maint: update copyright

[gnulib.git] / m4 / hypot.m4

diff --git a/m4/hypot.m4 b/m4/hypot.m4
index 1837a01..6c35054 100644 (file)
--- a/m4/hypot.m4
+++ b/m4/hypot.m4
@@ -1,5 +1,5 @@
-# hypot.m4 serial 2
-dnl Copyright (C) 2012 Free Software Foundation, Inc.
+# hypot.m4 serial 4
+dnl Copyright (C) 2012-2014 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.
@@ -9,11 +9,15 @@ AC_DEFUN([gl_FUNC_HYPOT],
   m4_divert_text([DEFAULTS], [gl_hypot_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
 
+  dnl Persuade glibc <math.h> to declare hypot().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Determine HYPOT_LIBM.
   gl_COMMON_DOUBLE_MATHFUNC([hypot])
 
   m4_ifdef([gl_FUNC_HYPOT_IEEE], [
     if test $gl_hypot_required = ieee && test $REPLACE_HYPOT = 0; then
+      AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
       AC_CACHE_CHECK([whether hypot works according to ISO C 99 with IEC 60559],
         [gl_cv_func_hypot_ieee],
         [
@@ -50,7 +54,13 @@ int main (int argc, char *argv[])
             ]])],
             [gl_cv_func_hypot_ieee=yes],
             [gl_cv_func_hypot_ieee=no],
-            [gl_cv_func_hypot_ieee="guessing no"])
+            [case "$host_os" in
+                       # Guess yes on glibc systems.
+               *-gnu*) gl_cv_func_hypot_ieee="guessing yes" ;;
+                       # If we don't know, assume the worst.
+               *)      gl_cv_func_hypot_ieee="guessing no" ;;
+             esac
+            ])
           LIBS="$save_LIBS"
         ])
       case "$gl_cv_func_hypot_ieee" in