Backport 'Explicitly destroy static Glib::RefPtr<>s on exit' from
Hombre57's hidpi-icons branch in GitHub (now merged to dev branch).
Also expose pixbufCache globally and explicitly .clear() it before exit().
Fixes the SIGABRT-on-exit issue.
Remove the wrapper that runs ulimit -c 0 before rawtherapee.
Enable OpenMP on i386 (uses GCC for now).
Shorten option descriptions so they don't get truncated.
Only add -msse2 on i386 and amd64, to fix broken aarch64/powerpc64 builds.
Fix various portlint warnings, removing USE_LDCONFIG.
PR: 205370
6002f358f4