Run vpp-configure on change to cmake config files.

Modify the dirs assignment in configure_check_timestamp to
add the build-data/platforms/$(PLATFORM).mk file, all the CMakeLists.txt
files in the $(PACKAGE_SOURCE) tree, and the $(PACKAGE_SOURCE)/cmake
directory.
(For example, for package vpp, $(PACKAGE_SOURCE) is <Top of Tree>/src).
Note that in an earlier era there was no build-data/platforms directory and
no CMakeLists.txt files.
Also, we tacitly assume that $(SOURCE_PATH_BUILD_DATA_DIRS) is only one
directory whereas ebuild has been used in environments where there are two
treetops.

Change-Id: I761219adbdb4c7e675bb12b3e7f052db68f0294c
Signed-off-by: Burt Silverman <burtms@gmail.com>

build-root/Makefile

@@ -625,6 +625,10 @@ configure_check_timestamp =						\
   mkdir -p $(PACKAGE_INSTALL_DIR) ;					\
   conf="$(TIMESTAMP_DIR)/$(CONFIGURE_TIMESTAMP)" ;			\
   dirs="$(call package_mk_fn,$(PACKAGE))				\
+	$(SOURCE_PATH_BUILD_DATA_DIRS)/platforms/$(PLATFORM).mk		\
+	$(wildcard $(call find_source_fn,$(PACKAGE_SOURCE))/cmake)	\
+	$(shell find $(call find_source_fn,$(PACKAGE_SOURCE))		\
+			-name CMakeLists.txt)				\
 	$(wildcard $(call find_source_fn,				\
 	             $(PACKAGE_SOURCE))$(PACKAGE_SUBDIR)/configure)	\
        $(MU_BUILD_ROOT_DIR)/config.site" ;				\