matchbox: apply libtool patch to matchbox-desktop

matchbox-desktop fails to build because it tries to read
/usr/lib/libxcb.la, which doesn't exist on a very basic system with no
development files instead. The buildroot-libtool.patch must therefore
be applied.

Unfortunately, matchbox doesn't yet use the autotools infrastructure,
so we have to manually apply the patch.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/matchbox/matchbox.mk

@@ -141,6 +141,7 @@ $(MATCHBOX_PL_DIR)/.unpacked: $(DL_DIR)/$(MATCHBOX_PL_SOURCE)
 $(MATCHBOX_DP_DIR)/.unpacked: $(DL_DIR)/$(MATCHBOX_DP_SOURCE)
 	$(MATCHBOX_CAT) $(DL_DIR)/$(MATCHBOX_DP_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) -
 	$(SED) 's:mbfolder\.png:mbtasks\.png:g' $(MATCHBOX_DP_DIR)/modules/tasks.c
+	toolchain/patch-kernel.sh $(MATCHBOX_DP_DIR) package/ buildroot-libtool.patch
 	touch $(MATCHBOX_DP_DIR)/.unpacked
 
 $(MATCHBOX_FK_DIR)/.unpacked: $(DL_DIR)/$(MATCHBOX_FK_SOURCE)