MIPS rustup depends on a too-new glibc

[nagisa]

root@debian:~# curl https://sh.rustup.rs -sSf | sh
info: downloading installer
/tmp/tmp.0SjgknXIdh/rustup-init: /lib/mips-linux-gnu/libc.so.6: version `GLIBC_2.25' not found (required by /tmp/tmp.0SjgknXIdh/rustup-init)

on my ~2 year old jessie-based MIPS VM.

[mati865]

#1536 bumped minimal GLIBC to 2.27

[kinnison]

Is this still an issue? I think we tweaked our builders a bit more since last year.