MFH: r522316 r522638 r522639

lang/rust: Simplify do-configure and garbage collect files/config.toml

lang/rust: fix powerpc64 elfv2 bootstrap

Apparently there were some issues with the previous one.

PR: 243253
Submitted by: mikael.urankar@gmail.com
Reported by: jhibbits, pkubaj
Tested by: pkubaj

lang/rust: increase build verbosity and produce better build logs

Approved by: ports-secteam blanket