override flags from compiletest

src/test/ui/proc-macro/musl-proc-macro.rs

@@ -1,6 +1,7 @@
 // Test proc-macro crate can be built without addtional RUSTFLAGS
 // on musl target
-
+// override -Ctarget-feature=-crt-static from compiletest
+// compile-flags: -Ctarget-feature=
 // build-pass
 // only-musl
 #![crate_type = "proc-macro"]