maint: update copyright

[gnulib.git] / m4 / check-math-lib.m4

diff --git a/m4/check-math-lib.m4 b/m4/check-math-lib.m4
index fb9cb94..a3894aa 100644 (file)
--- a/m4/check-math-lib.m4
+++ b/m4/check-math-lib.m4
@@ -1,32 +1,32 @@
-# check-math-lib.m4 serial 1
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# check-math-lib.m4 serial 4
+dnl Copyright (C) 2007, 2009-2014 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.
 dnl
-dnl AC_CHECK_MATH_LIB (VARIABLE, EXPRESSION)
+dnl gl_CHECK_MATH_LIB (VARIABLE, EXPRESSION [, EXTRA-CODE])
 dnl
-dnl Checks whether EXPRESSION requires -lm to compile and link.  If so, sets
-dnl the shell VARIABLE to -lm, otherwise to the empty string.
+dnl Sets the shell VARIABLE according to the libraries needed by EXPRESSION
+dnl to compile and link: to the empty string if no extra libraries are needed,
+dnl to "-lm" if -lm is needed, or to "missing" if it does not compile and
+dnl link either way.
 dnl
-dnl Example: AC_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);])
+dnl Example: gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);])
 AC_DEFUN([gl_CHECK_MATH_LIB], [
   save_LIBS=$LIBS
-  $1=?
+  $1=missing
   for libm in "" "-lm"; do
     LIBS="$save_LIBS $libm"
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       double x;],
-      [$2],
+    AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+         #ifndef __NO_MATH_INLINES
+         # define __NO_MATH_INLINES 1 /* for glibc */
+         #endif
+         #include <math.h>
+         $3
+         double x;]],
+      [$2])],
       [$1=$libm
 break])
   done
   LIBS=$save_LIBS
-  if test "$$1" = "?"; then
-    $1=
-  fi
 ])