Rollup merge of #131168 - madsmtm:target-info-psx-os, r=davidtwco

Fix `target_os` for `mipsel-sony-psx`

Previously set to `target_os = "none"` and `target_env = "psx"` in [the PR introducing the target](#102689), but although the Playstation 1 is _close_ to a bare metal target in some regards, it's still very much an operating system, so we should instead set `target_os = "psx"`.

This also matches the `mipsel-sony-psp` target, which sets `target_os = "psp"`.

CC target maintainer ``@ayrtonm.``

If there's any code out there that uses `cfg(target_env = "psx")`, they can use `cfg(any(target_os = "psx", target_env = "psx"))` until they bump their MSRV to a version where this is fully fixed.

compiler/rustc_target/src/spec/targets/mipsel_sony_psx.rs

@@ -14,8 +14,11 @@ pub(crate) fn target() -> Target {
         arch: "mips".into(),
 
         options: TargetOptions {
-            os: "none".into(),
-            env: "psx".into(),
+            // The Playstation 1 is mostly bare-metal, but the BIOS does provide some a slight bit
+            // of functionality post load, so we still declare it as `cfg!(target_os = "psx")`.
+            //
+            // See <https://github.com/rust-lang/rust/pull/131168> for details.
+            os: "psx".into(),
             vendor: "sony".into(),
             linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
             cpu: "mips1".into(),

tests/ui/check-cfg/well-known-values.stderr

@@ -156,7 +156,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_env = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_env` are: ``, `gnu`, `msvc`, `musl`, `newlib`, `nto70`, `nto71`, `ohos`, `p1`, `p2`, `psx`, `relibc`, `sgx`, and `uclibc`
+   = note: expected values for `target_env` are: ``, `gnu`, `msvc`, `musl`, `newlib`, `nto70`, `nto71`, `ohos`, `p1`, `p2`, `relibc`, `sgx`, and `uclibc`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -210,7 +210,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_os = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -294,7 +294,7 @@ LL | #[cfg(target_os = "linuz")] // testing that we suggest `linux`
    |                   |
    |                   help: there is a expected value with a similar name: `"linux"`
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: 30 warnings emitted