ok, that happens only if the GLX libs (GL and so on...) do load the installer x11 libs which will look in /usr/share/x11. If the GLX libs do load my x11 libs, it's fine because those libs will look in the the proper share/x11 dir!
I did check the environment, now it seems my 32 bits libs are prioritized by default in LD_LIBRARY_PATH. Don't know why but probably my 32 bits ldconfig in PATH did something.
The installer has changed significantly.
Would need new and full testing with inventory of all the issues encountered on a lean elf/linux distro.
Nothing extracted yet.
If you don't have some stuff (xlocale? xkb?) in /usr/share/X11 and have those in /share/X11 or /usr/local/share/X11, it will crash.