Problem with AC_PROVIDE_ and libtool.m4

[Owen Taylor]

While using building libtool 1.4.3, I ran into failures in the test
suite due to AC_LIBTOOL_DLOPEN not working properly after running
autoreconf. The mdemo test was falling back to the dlpreopen support.

After tracing it down for a while, it turned out the the check for the
function being provided wasn't working properly (autoconf-2.54, GNU
m4-1.4.1).  Switching to using AC_PROVIDE_IFELSE() fixed the problem.

[
 Hmmm... I suppose this might be a autoconf-2.5x feature; I don't
 know if it is possible to fix this problem in a way that is compatible
 with both 2.13 and 2.53/2.54.
]

Patch appended. 

Regards,
                                        Owen

--- libtool-1.4.3/libtool.m4.providedlopen      Sun Nov  3 17:26:01 2002
+++ libtool-1.4.3/libtool.m4    Sun Nov  3 17:27:08 2002
@@ -70,8 +70,8 @@
 AC_CHECK_TOOL(RANLIB, ranlib, :)
 AC_CHECK_TOOL(STRIP, strip, :)
 
-ifdef([AC_PROVIDE_AC_LIBTOOL_DLOPEN], enable_dlopen=yes, enable_dlopen=no)
-ifdef([AC_PROVIDE_AC_LIBTOOL_WIN32_DLL],
+AC_PROVIDE_IFELSE([AC_LIBTOOL_DLOPEN], enable_dlopen=yes, enable_dlopen=no)
+AC_PROVIDE_IFELSE([AC_LIBTOOL_WIN32_DLL], 
 enable_win32_dll=yes, enable_win32_dll=no)
 
 AC_ARG_ENABLE(libtool-lock,