fixup! doc: add a version check for Doxygen

doc/doxygen/Makefile

@@ -32,10 +32,12 @@ html: src/changelog.md src/coc.md src/governance.md
 	@echo ""
 	@echo "RIOT documentation successfully generated at file://$(RIOTBASE)/doc/doxygen/html/index.html"
 	@DOXYGEN_VERSION=$$(doxygen --version | awk '{print $$1}'); \
-		awk 'BEGIN {if ("'$$DOXYGEN_VERSION'" < "'$(DOXYGEN_MIN_VERSION)'") { \
-		print "$(COLOR_RED)Warning: Doxygen version " "'$$DOXYGEN_VERSION'" " is too old. " \
-		"It is recommended to use at least version $(DOXYGEN_MIN_VERSION) " \
-		"to avoid incorrectly formatted output.$(COLOR_RESET)"}}'
+	if [ "`{ echo "$(DOXYGEN_MIN_VERSION)"; echo "$$DOXYGEN_VERSION"; } | \
+		sort -V | head -n1`" != "$(DOXYGEN_MIN_VERSION)" ]; then \
+		$(COLOR_ECHO) "$(COLOR_RED)Warning: Doxygen version $$DOXYGEN_VERSION is too old." \
+		"It is recommended to use at least version $(DOXYGEN_MIN_VERSION)" \
+		"to avoid incorrectly formatted output.$(COLOR_RESET)"; \
+	fi
 
 .PHONY: check
 check: src/changelog.md src/coc.md src/governance.md