Makefile: rebuild current objs in default:
Makefile: mrproper: recreate obj/
Makefile: prettify the build output
Makefile: cflags
dist/prepare: use out=dist by default
Revert "dist/prepare: use out=dist by default"

This reverts commit c38aa435a22bd85c8ac5330e2dfcade9c5e5dc34.

On the second thought, no.