Make it work with autoconf-2.50 as well.

diff --git a/m4/libtool.m4 b/m4/libtool.m4
index 0b2a6181c0b902059924c32618b3197ecdd905bf..3eb0f63587ca675992de5b9a7d21ce188e48e457 100644 (file)
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -23,7 +23,7 @@
 ## the same distribution terms that you use for the rest of that program.
 
 # The next line was added by Bruno Haible 2001-06-08.
-undefine([symbols])
+builtin([undefine],[symbols])
 
 # serial 46 AC_PROG_LIBTOOL
 AC_DEFUN([AC_PROG_LIBTOOL],