As discussed in #11876, the interp files work fine on Linux (and other
platforms) too, and this allows to properly redirect to the working
interpreter found at configure time, without touching the scripts'
shebang.
- Fix "no icons" errors generating loaders.cache with .cmd (CI-Cross).
! This is a sub-optimal fix, but it's better than a useless build.
- Fix "no interpreter" errors generating .interp with Meson (CI-Native)
and generating .interp and copying .typelib with .cmd (Local-Native).
! This is a sub-optimal fix to Local-Native, but plug-ins will work.
- Fix "no iso" error copying iso_639.xml with Meson (Local-Native).
