configure: Set the correct lib target for arm/wince dlltool

The correct machine name for dlltool is arm-wince.
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

configure

@@ -2407,7 +2407,7 @@ case $target_os in
             enable malloc_aligned
             LIBTARGET="i386:x86-64"
         elif enabled arm; then
-            LIBTARGET=arm
+            LIBTARGET=arm-wince
         fi
         shlibdir_default="$bindir_default"
         disable ffserver