libpcap: fix PKG_CONFIG_DEPENDS for rpcapd

This fix allows trigger a rerun of Build/Configure when
rpcapd was selected.
Signed-off-by: NJianhui Zhao <zhaojh329@gmail.com>
(cherry picked from commit 6902af4f)

package/libs/libpcap/Makefile

@@ -21,6 +21,8 @@ PKG_LICENSE_FILES:=LICENSE
 
 PKG_ASLR_PIE_REGULAR:=1
 
+PKG_CONFIG_DEPENDS := CONFIG_PACKAGE_rpcapd
+
 include $(INCLUDE_DIR)/package.mk
 include $(INCLUDE_DIR)/cmake.mk