Auto merge of rust-lang#135336 - tshepang:patch-5, r=jieyouxu

clarify and document needs-dynamic-linking

try-job: test-various

Author: bors

src/doc/rustc-dev-guide/src/tests/directives.md

@@ -192,6 +192,8 @@ settings:
   specified atomic widths, e.g. the test with `//@ needs-target-has-atomic: 8,
   16, ptr` will only run if it supports the comma-separated list of atomic
   widths.
+- `needs-dynamic-linking` - ignores if target does not support dynamic linking
+  (which is orthogonal to it being unable to create `dylib` and `cdylib` crate types)
 
 The following directives will check LLVM support:
 

tests/ui/invalid-compile-flags/crate-type-flag.rs

@@ -17,12 +17,12 @@
 //@[staticlib] compile-flags: --crate-type=staticlib
 //@[staticlib] check-pass
 
-//@[dylib] ignore-musl (dylibs are not supported)
-//@[dylib] ignore-wasm (dylibs are not supported)
+//@[dylib] ignore-musl (dylib is supported, but musl libc is statically linked by default)
+//@[dylib] ignore-wasm (dylib is not supported)
 //@[dylib] compile-flags: --crate-type=dylib
 //@[dylib] check-pass
 
-//@[cdylib] ignore-musl (cdylibs are not supported)
+//@[cdylib] ignore-musl (cdylib is supported, but musl libc is statically linked by default)
 //@[cdylib] compile-flags: --crate-type=cdylib
 //@[cdylib] check-pass
 
@@ -39,9 +39,7 @@
 //@[multivalue] compile-flags: --crate-type=lib,rlib,staticlib
 //@[multivalue] check-pass
 
-//@[multivalue_combined] ignore-musl (dylibs are not supported)
-//@[multivalue_combined] ignore-wasm (dylibs are not supported)
-//@[multivalue_combined] compile-flags: --crate-type=lib,rlib,staticlib --crate-type=dylib
+//@[multivalue_combined] compile-flags: --crate-type=lib,rlib --crate-type=staticlib
 //@[multivalue_combined] check-pass
 
 // `proc-macro` is accepted, but `proc_macro` is not.