Rollup merge of rust-lang#57465 - jethrogb:jb/stablize-cfg-target-vendor, r=joshtriplett,Centril

Stabilize cfg_target_vendor

This stabilizes the use of `cfg(target_vendor = "...")` and removes the corresponding `cfg_target_vendor` feature. Other unstable cfgs remain behind their existing feature gates.

This functionality was added back in 2015 in rust-lang#28612 to complete the coverage of target tuples (`<arch><sub>-<vendor>-<os>-<env>`). [RFC 131](https://github.com/rust-lang/rfcs/blob/master/text/0131-target-specification.md) governs the target specification, not including `target_vendor` seems to have just been an oversight. `target_os`, `target_family`, and `target_arch` are stable as of 1.0.0. `target_env` was also not mentioned in RFC 131, was added in rust-lang#24777, never behind a feature_gate, and insta-stable at 1.1.0.

The functionality is tested in [test/run-pass/cfg/cfg-target-vendor.rs](https://github.com/rust-lang/rust/blob/master/src/test/run-pass/cfg/cfg-target-vendor.rs).

Closes rust-lang#29718

Author: Centril

src/libpanic_abort/lib.rs

@@ -12,7 +12,7 @@
 #![panic_runtime]
 #![allow(unused_features)]
 
-#![feature(cfg_target_vendor)]
+#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(core_intrinsics)]
 #![feature(libc)]
 #![feature(nll)]

src/librustdoc/clean/cfg.rs

@@ -370,6 +370,7 @@ impl<'a> fmt::Display for Html<'a> {
                         "pc" => "PC",
                         "rumprun" => "Rumprun",
                         "sun" => "Sun",
+                        "fortanix" => "Fortanix",
                         _ => ""
                     },
                     ("target_env", Some(env)) => match &*env.as_str() {
@@ -378,6 +379,7 @@ impl<'a> fmt::Display for Html<'a> {
                         "musl" => "musl",
                         "newlib" => "Newlib",
                         "uclibc" => "uClibc",
+                        "sgx" => "SGX",
                         _ => "",
                     },
                     ("target_endian", Some(endian)) => return write!(fmt, "{}-endian", endian),

src/libstd/lib.rs

@@ -238,7 +238,7 @@
 #![feature(c_variadic)]
 #![feature(cfg_target_has_atomic)]
 #![feature(cfg_target_thread_local)]
-#![feature(cfg_target_vendor)]
+#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(char_error_internals)]
 #![feature(compiler_builtins_lib)]
 #![feature(concat_idents)]

src/libsyntax/feature_gate.rs

@@ -244,9 +244,6 @@ declare_features! (
     // rustc internal
     (active, omit_gdb_pretty_printer_section, "1.5.0", None, None),
 
-    // Allows `cfg(target_vendor = "...")`.
-    (active, cfg_target_vendor, "1.5.0", Some(29718), None),
-
     // Allows attributes on expressions and non-item statements.
     (active, stmt_expr_attributes, "1.6.0", Some(15701), None),
 
@@ -686,6 +683,8 @@ declare_features! (
     (accepted, if_while_or_patterns, "1.33.0", Some(48215), None),
     // Allows `use x::y;` to search `x` in the current scope.
     (accepted, uniform_paths, "1.32.0", Some(53130), None),
+    // Allows `cfg(target_vendor = "...")`.
+    (accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must
@@ -1181,7 +1180,6 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeGate)] = &[
 // cfg(...)'s that are feature gated
 const GATED_CFGS: &[(&str, &str, fn(&Features) -> bool)] = &[
     // (name in cfg, feature, function to check if the feature is enabled)
-    ("target_vendor", "cfg_target_vendor", cfg_fn!(cfg_target_vendor)),
     ("target_thread_local", "cfg_target_thread_local", cfg_fn!(cfg_target_thread_local)),
     ("target_has_atomic", "cfg_target_has_atomic", cfg_fn!(cfg_target_has_atomic)),
     ("rustdoc", "doc_cfg", cfg_fn!(doc_cfg)),

src/libtest/lib.rs

@@ -23,7 +23,7 @@
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
 #![feature(asm)]
-#![feature(cfg_target_vendor)]
+#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(fnbox)]
 #![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc))]
 #![feature(nll)]

src/libunwind/lib.rs

@@ -1,7 +1,7 @@
 #![no_std]
 #![unstable(feature = "panic_unwind", issue = "32837")]
 
-#![feature(cfg_target_vendor)]
+#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(link_cfg)]
 #![feature(nll)]
 #![feature(staged_api)]

src/test/run-pass/cfg/cfg-target-vendor.rs

@@ -1,6 +1,4 @@
 // run-pass
-#![feature(cfg_target_vendor)]
-
 #[cfg(target_vendor = "unknown")]
 pub fn main() {
 }