Auto merge of #80315 - tmiasko:ignore-proc-macros, r=Mark-Simulacrum
Auto merge of #80315 - tmiasko:ignore-proc-macros, r=Mark-Simulacrum

Ignore proc-macros when assembling rustc libdir

Fixes #80294.

graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust