Build 'file' for the host as well as the target. If the host system has a...

Build 'file' for the host as well as the target. If the host system has a version older than that being built for buildroot, the target build will fail. So, we build 'file' for the host and add actually add '$(TOOL_BUILD_DIR)/bin' to the TARGET_PATH so that it takes precedence over the host system version.