Drop -L%{_libdir} from linking so that just built libxfce4ui is before
older system version in linker search path.

--- libxfce4ui-4.18.0/libxfce4kbd-private/Makefile.am.orig	2022-10-30 12:33:05.000000000 +0100
+++ libxfce4ui-4.18.0/libxfce4kbd-private/Makefile.am	2022-12-26 15:50:55.466362077 +0100
@@ -61,7 +61,6 @@ libxfce4kbd_private_3_la_LDFLAGS = \
 	-version-info $(LIBXFCE4KBD_PRIVATE_VERINFO) \
 	-export-symbols-regex "^[^_].*" \
 	-no-undefined \
-	$(LIBX11_LDFLAGS) \
 	$(PLATFORM_LDFLAGS)
 
 libxfce4kbd_private_3_la_LIBADD = \