Test failures with `build.description` set (1.89.0 regression)

[xry111]

When build.description is set, various tests fail like

diff of stderr:

4   LL | #![feature(unsized_locals)]
5      |            ^^^^^^^^^^^^^^ feature has been removed
6      |     
-      = note: removed in 1.89.0 (you are using $RUSTC_VERSION)
+      = note: removed in 1.89.0 (you are using $RUSTC_VERSION (for BLFS r12.3-1175))
8      = note: removed due to implementation concerns; see https://github.com/rust-lang/rust/issues/111942
9   
10  error: aborting due to 1 previous error 

[jieyouxu]

This was resolved by not including that current version string (#142943).