Fix libtool detection of --as-needed flag

The fix for -Wl,--as-needed in commit b0f9477f assumes that
--as-needed/--no-as-needed is the only option given in a -Wl line.
However, it is perfectly valid to specify multiple flags comma
separated after a single -Wl (e.g. the default LDFLAGS in Arch
Linux makepkg.conf).

Adjust the fix so it detect --as-needed in a more general context

> readelf -d lib/libalpm/.libs/libalpm.so.?.?.? | grep NEEDED | wc -l
Before: 13
After: 5

Signed-off-by: Allan McRae <allan@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>

ltmain.sh

@@ -5800,9 +5800,12 @@ func_mode_link ()
 	arg=$func_stripname_result
 	;;
 
-      -Wl,--as-needed|-Wl,--no-as-needed)
-	deplibs="$deplibs $arg"
-	continue
+      -Wl,*--as-needed*)
+	deplibs="$deplibs $wl--as-needed"
+	;;
+
+      -Wl,*--no-as-needed*)
+	deplibs="$deplibs $wl--no-as-needed"
 	;;
 
       -Wl,*)