Revert "Completely disable distcheck"

This reverts commit 1430229.

Author: brson

mk/dist.mk

@@ -288,7 +288,8 @@ endif
 
 dist: $(MAYBE_DIST_TAR_SRC) dist-tar-bins $(MAYBE_DIST_DOCS)
 
-distcheck:
+distcheck: $(MAYBE_DISTCHECK_TAR_SRC) distcheck-tar-bins $(MAYBE_DISTCHECK_DOCS)
+	$(Q)rm -Rf tmp/distcheck
 	@echo
 	@echo -----------------------------------------------
 	@echo "Rust ready for distribution (see ./dist)"