I'm no expert on debian packaging, but this looks like a reasonable update of the previous gnustep-make package; many files have changed but each change seems small, but since I don't know how the packaging system works, I can't judge whether the changes are all good ...
But I *have* tried out the package, and as maintainer of gnustep-base, I'm very familiar with using gnustep-make. The source package built without errors in a chroot. I checked installing the resulting binary packages out-of-order to be sure that inter-package dependency information was correct. I then installed the resulting binary packages in order, without trouble/errors. I used the installation of gnustep-make to build the gnustep core libraries, and it seems to be working well. This package is for the current stable upstream release of gnustep-make (2.6.8), which is a huge improvement over the version currently packaged for debian; 2.6.6 is from 2013 and was superseded by 2.6.7 a year ago.