fix bundled libtom configure flag

[Mike Frysinger]

the current flag treats --disable-bundled-libtom like enable.  this patch fixes it.
-mike

diff -r 93e04b9ff676 configure.ac
--- a/configure.ac	Wed Oct 09 22:24:39 2013 +0800
+++ b/configure.ac	Sat Oct 12 16:36:07 2013 -0400
@@ -365,9 +365,15 @@ AC_CHECK_FUNCS(logout updwtmp logwtmp)
 
 AC_ARG_ENABLE(bundled-libtom,
 	[  --enable-bundled-libtom       Use bundled libtomcrypt/libtommath even if a system version exists],
-	[ 
-		BUNDLED_LIBTOM=1
-		AC_MSG_NOTICE(Forcing bundled libtom*)
+	[
+		if test "x$enableval" = "xyes"; then
+			BUNDLED_LIBTOM=1
+			AC_MSG_NOTICE(Forcing bundled libtom*)
+		else
+			BUNDLED_LIBTOM=0
+			AC_CHECK_LIB(tomcrypt, register_cipher, , BUNDLED_LIBTOM=1)
+			AC_CHECK_LIB(tommath, mp_exptmod, , BUNDLED_LIBTOM=1)
+		fi
 	],
 	[
 		BUNDLED_LIBTOM=0
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: This is a digitally signed message part.
Url : http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/attachments/20131012/0b5e3770/attachment.sig