Changes

drop loong64 patch #1024359 applied in libffi/3.4.4-2

drop loong64 patch #1031850 resolved in gcc-13

adapt to linux-libc-dev having become a:all+m-a:foreign

Most of the time, we no longer have to rebuild linux-libc-dev.
Sometimes, it's missing headers though and then we need to rebuild it,
but not as a cross build, but an indep-only build.

linux: circumvent control generation protection more reliably

reenable building of gcc-13 common libraries

gcc-14 entered unstable.

adapt linux patching to toml based configuration