libplist: add missing pkgconfig files in libplist 2.2

Closes #12571.

Same fix as Debian, see:
libimobiledevice/libplist@137716d#commitcomment-40099153

Signed-off-by: Espen Jürgensen <espenjurgensen+openwrt@gmail.com>

libs/libplist/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libplist
 PKG_VERSION:=2.2.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://www.libimobiledevice.org/downloads
@@ -92,7 +92,10 @@ define Build/InstallDev
 	$(INSTALL_DIR) $(1)/usr/lib
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libplist-2.0*.so* $(1)/usr/lib/
 	$(INSTALL_DIR) $(1)/usr/lib/pkgconfig
-	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libplist*.pc $(1)/usr/lib/pkgconfig/
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libplist++-2.0.pc $(1)/usr/lib/pkgconfig/
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libplist-2.0.pc $(1)/usr/lib/pkgconfig/
+	$(LN) libplist++-2.0.pc $(1)/usr/lib/pkgconfig/libplist++.pc
+	$(LN) libplist-2.0.pc $(1)/usr/lib/pkgconfig/libplist.pc
 endef
 
 define Package/libplist/install