suggestion: samurai

[René J. V. Bertin]

A QtWebEngine rebuild in the same build.dir (without preceding `make clean`) 
completed just fine using ninja symlinked `samu` (a part of the tree was 
rebuild).

Samu is also able to build ninja itself (if you skip the ninja bootstrap 
procedure and copy samu to ${worksrcpath}/ninja).

Here's an implementation of the port in case

 anyone wants to test:

https://github.com/RJVB/macstrop/blob/master/devel/samurai/Portfile

R