refactor: use grep -E instead of egrep (#2141)

Co-authored-by: Jacob Coffee <[email protected]>

Author: kxxt

Diff for: Makefile

@@ -4,7 +4,7 @@ default:
 	@$(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null\
         | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}'\
         | sort\
-        | egrep -v -e '^[^[:alnum:]]' -e '^$@$$'
+        | grep -E -v -e '^[^[:alnum:]]' -e '^$@$$'
 	@echo
 	@exit 1