+ DOXYGEN_CMD = if ( $(BASE_DOXYGEN_CMD) 2>&1 | grep -v "warning: ignoring unsupported tag" ;); then exit 1; fi;\r
+else ifeq ($(DOXYGEN_FAIL_ON_WARNING), N)\r
+ DOXYGEN_CMD = $(BASE_DOXYGEN_CMD)\r
+else\r
+ $(error DOXYGEN_FAIL_ON_WARNING must be Y or N.)\r