Auto merge of #69519 - 12101111:remove-proc-macro-check, r=nagisa

Don't use static crt by default when build proc-macro

Don't check value of `crt-static` when build proc-macro crates, since they are always built dynamically.
For more information, see https://github.com/rust-lang/cargo/issues/7563#issuecomment-591965320
I hope this will fix issues about compiling `proc_macro` crates on musl host without bring more issues.
Fix https://github.com/rust-lang/cargo/issues/7563

src/test/ui/proc-macro/crt-static.rs

@@ -0,0 +1,16 @@
+// Test proc-macro crate can be built without addtional RUSTFLAGS
+// on musl target
+// override -Ctarget-feature=-crt-static from compiletest
+// compile-flags: -Ctarget-feature=
+// ignore-wasm32
+// build-pass
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+
+#[proc_macro_derive(Foo)]
+pub fn derive_foo(input: TokenStream) -> TokenStream {
+    input
+}