[Bug lto/106328] Build doesn't respect -j N flag

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106328

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
If it is possible to query the '-j=N' setting from make via the jobserver
connection then it might be practical to auto-tune
lto-max-streaming-parallelism
to that setting at least (that's still prone to N*N sub-processes).