X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Falloca.m4;h=4b978e137cbe7c2d9f76baa6546764f6e2f7a0a6;hb=42d1eda5dcce2d68deab7a642e7f29bcd7144a0d;hp=fa90eef0e0762d0f3316a3493f95572a0815582e;hpb=ce3865c2e13733b6d97cb897210e9fb0145e7152;p=gnulib.git

diff --git a/m4/alloca.m4 b/m4/alloca.m4
index fa90eef0e..4b978e137 100644
--- a/m4/alloca.m4
+++ b/m4/alloca.m4
@@ -1,5 +1,5 @@
-# alloca.m4 serial 7
-dnl Copyright (C) 2002-2004, 2006 Free Software Foundation, Inc.
+# alloca.m4 serial 9
+dnl Copyright (C) 2002-2004, 2006, 2007, 2009 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.
@@ -17,29 +17,28 @@ AC_DEFUN([gl_FUNC_ALLOCA],
 
   # Define an additional variable used in the Makefile substitution.
   if test $ac_cv_working_alloca_h = yes; then
-    AC_CACHE_CHECK([whether alloca must be replaced], [gl_cv_rpl_alloca], [
+    AC_CACHE_CHECK([for alloca as a compiler built-in], [gl_cv_rpl_alloca], [
       AC_EGREP_CPP([Need own alloca], [
 #if defined __GNUC__ || defined _AIX || defined _MSC_VER
-	  Need own alloca
+        Need own alloca
 #endif
-	], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+        ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
     ])
     if test $gl_cv_rpl_alloca = yes; then
-      AC_DEFINE([HAVE_ALLOCA], 1,
-	[Define to 1 if you have `alloca' after including <alloca.h>,
-	 a header that may be supplied by this distribution.])
+      dnl OK, alloca can be implemented through a compiler built-in.
+      AC_DEFINE([HAVE_ALLOCA], [1],
+        [Define to 1 if you have 'alloca' after including <alloca.h>,
+         a header that may be supplied by this distribution.])
       ALLOCA_H=alloca.h
     else
+      dnl alloca exists as a library function, i.e. it is slow and probably
+      dnl a memory leak. Don't define HAVE_ALLOCA in this case.
       ALLOCA_H=
     fi
   else
     ALLOCA_H=alloca.h
   fi
   AC_SUBST([ALLOCA_H])
-
-  AC_DEFINE(HAVE_ALLOCA_H, 1,
-    [Define HAVE_ALLOCA_H for backward compatibility with older code
-     that includes <alloca.h> only if HAVE_ALLOCA_H is defined.])
 ])
 
 # Prerequisites of lib/alloca.c.