Rename cfg_match! to cfg_select!

At [1] it was pointed out that `cfg_match!` syntax does not actually
align well with match syntax, which is a possible source of confusion.
The comment points out that usage is instead more similar to ecosystem
`select!` macros. Rename `cfg_match!` to `cfg_select!` to match this.

Tracking issue: rust-lang/rust#115585

[1]: rust-lang/rust#115585 (comment)

Author: tgross35

src/concurrency/mod.rs

@@ -9,7 +9,7 @@ mod vector_clock;
 pub mod weak_memory;
 
 // Import either the real genmc adapter or a dummy module.
-cfg_match! {
+cfg_select! {
     feature = "genmc" => {
         mod genmc;
         pub use self::genmc::{GenmcCtx, GenmcConfig};

src/lib.rs

@@ -1,5 +1,5 @@
 #![feature(rustc_private)]
-#![feature(cfg_match)]
+#![feature(cfg_select)]
 #![feature(float_gamma)]
 #![feature(float_erf)]
 #![feature(map_try_insert)]

src/shims/unix/fs.rs

@@ -90,7 +90,7 @@ impl UnixFileDescription for FileHandle {
         op: FlockOp,
     ) -> InterpResult<'tcx, io::Result<()>> {
         assert!(communicate_allowed, "isolation should have prevented even opening a file");
-        cfg_match! {
+        cfg_select! {
             all(target_family = "unix", not(target_os = "solaris")) => {
                 use std::os::fd::AsRawFd;