[Bug target/71989] aarch64 musl bootstrap fails for out-of-tree builds

[timo.teras at iki dot fi]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71989

--- Comment #3 from Timo Teräs <timo.teras at iki dot fi> ---
(In reply to Andrew Pinski from comment #2)
> Are we sure this is not a musl issue?

Same source code / out-of-tree bootstrap in musl environment works for
triplets:
 armhf-alpine-linux-muslgnueabihf
 i586-alpine-linux-musl
 x86_64-alpine-linux-musl

But it is possible there's something in musl aarch64 specific headers, or in
the build process that triggers only in musl/busybox environment. For example,
it could be also some sed/awk script that depends on GNU extensions, or even
busybox bug.

I'll try to compare in-tree and out-of-tree builds see if I can pinpoint this
to something specific.