Hi! I'm Daniel Trujillo,


This is my first-time-ever contribution to GNU Guix, so please, don't 
hold any nitpick to yourself!! :)


I don't know if these kind of packages are of interest, but this is 
PrusaSlicer [0], a software to prepare 3D printings (hence I put it in 
engineering.scm).

The packaged version, 2.3.3 is the latest stable available at this 
moment. But this version has as important problem [1]: It cannot be 
invoked just naming the executable (through $PATH), because then, it 
can't locate the resources directory. I learned **the hard way** that 
the fix was applied *after* the release of the 2.3.3 version, so I 
decided to backport the fix adding a patch because it's a show-stopper 
to have to type the path to the executable in /gnu/store/... That's the 
reason why the patch attached to this email contains, not only the 
additions to engineering.scm, but also a patch that implements the 
solution in the version 2.3.3 codebase (It's quite simple, it uses a 
boost function to determine the path to the executable rather than 
relying on argv[0]).


Known improvable things:
* It's configured to use GTK3. After many attempts to compile it under 
GTK2 in a guix environment, sometimes it detected GTK right away, and 
some ether times I had to add more includes. It wasn't quite reliable 
and, according to the convention followed in gtk+ packages, probably it 
would be better that prusa-slicer uses GTK3, and a hypothetical future 
GTK2 version would be called prusa-slicer-gtk2.

* In order for the above $PATH issue fix to work, it's crucial that the 
cmake variable SLIC3R_FHS is set to off. This is the default value 
according to the CMakeLists.txt, but because it's so important, probably 
it should have been included in the configure-flags argument? Just for 
clarity.

* Currently, the version displayed in the title bar is 
"....2.3.3+UNKNOWN". This is because of another cmake option not set. It 
doesn't have any influence in the software, as far as I know, but it's 
arguably ugly. The version I currently use, doesn't display that in the 
title bar, but it does in the "About" window, and it says 
".....2.3.3+linux-64". Maybe something like "GNU Guix" would be 
prettier. But if I have to include the arch, I would have to dig deeper 
into package definitions ^_^'''


I hope everything is in order, I'm looking forward to see your comments, 
and hope I can start contributing more packages to Guix!!


Cheers,

Dani.


[0] https://www.prusa3d.es/prusaslicer/

[1] https://github.com/prusa3d/PrusaSlicer/issues/5542