I do agree that VPATH is helpful, but you'd still need to put the Makefile into the build directory in that case, which is distasteful, as it's not a built file

I do agree that VPATH is helpful, but you'd still need to put the Makefile into the build directory in that case, which is distasteful, as it's not a built file. Also you can't really get around specifying the files or searching, unless you have one c file per executable.