Missing icons in GIMP 2.10 custom compilation

[Sadakokiri]

Hi, I just compiled GIMP 2.10.38 (under an up-to-date Archlinux) from the sources in download.gimp.org, after a couple of tiny fix to get rid of some errors, and now I am trying to execute it without installation.

It seems to work well from the source directory when I run the command "GIMP2_DATADIR=$(pwd) app/gimp-2.10", but (most of) the UI icons are replaced by papers with gray warning signs: See my attachment "no-icons_warn.png".

I suspected the icon management to be an XDG stuff, and since I noticed the icons are present in the "icon" sub-folder of the current directory, I prepended the command line with "XDG_DATA_DIRS=$(pwd)", which changed the icons but not in a way that pleased me: See my attachment "no-icons_cross.png".

I am far from being an expert about Gimp/GTK and FreeDesktop icon management, does somebody know why the icons are missing? Should I tell GIMP where to find them? How?

*** Note ***
The edition I made on the sources are unrelated, they are :

1. Replaced the line 1372 of the file "plug-ins/file-tiff/file-tiff-load.c" by something like
gdouble xfix, yfix; gimp_image_get_resolution(*image, &xfix, &yfix); xres = xfix; yres = yfix;

2. Replaced the line 2143 of the file "plug-ins/metadata/metadata-editor.c" by something like
if (!g_strv_contains((const gchar* const*)values, equiv_values[evi]))

[Ofnuts]

What "prefix" do you use in your builds and where are the files installed? I haven't compiled 2.10.x since 2.10.34 is out it it used to work fine (and 3.0 works fine too). This likely not a problem with the code but with your build setup.

[Sadakokiri]

Thank you for your reply.
Well, I didn't know the concept of prefix so I just compiled the sources as is, by running in the source directory:
./configure --disable-python CFLAGS='-std=gnu11' && make

I agree this is likely not a problem with the code.
When you have built the version 2.10.34, did you installed it before running, or did you run the executable from the compilation folder?

[Ofnuts]

It was quite long-winded at the beginning.

Since I can run several Gimp versions in parallel my development structure for a given version looks like this:

Code:

/Gimp-dev/2.10.34
├── build
│   ├── babl
│   ├── gegl
│   ├── gimp
│   ├── GIMP-Lensfun
│   ├── GMIC-3.1.6
│   ├── libmypaint
│   ├── mypaint-brushes
│   ├── pango-1.47.0
│   └── resynthesizer
├── extra
└── run
   ├── bin
   ├── etc
   ├── include
   ├── lib
   ├── libexec
   └── share

• the root (/Gimp-dev/2.10.34 here) contains a script that is sourced to set up the proper environment
  
• build holds the source directories (git pull from repos for babl/gegl/gimp, tarballs for others)
  
• as you can see Gimp added a requirement for a recent version of pango so I had to add it to the mix.
  
• the "prefix" points to the run directory
  
• after a successful build the products are installed under run (so for instance the Gimp executable ends up as /Gimp-dev/2.10.34/run/bin/gimp-2.10.
  
• I start Gimp through a script that sets up the proper PATH/LD_LIBRAY_PATH/GI_TYPELIB_PATH and Gimp profile directory