tests/run-make: update mte-ffi to use gcc as the c compiler expli…

…citly

tests/run-make/mte-ffi/rmake.rs

@@ -1,14 +1,12 @@
-// Tests that MTE tags and values stored in the top byte of a pointer (TBI) are
-// preserved across FFI boundaries (C <-> Rust).
-// This test does not require MTE: whilst the test will use MTE if available, if it is not,
-// arbitrary tag bits are set using TBI.
+//! Tests that MTE tags and values stored in the top byte of a pointer (TBI) are preserved across
+//! FFI boundaries (C <-> Rust). This test does not require MTE: whilst the test will use MTE if
+//! available, if it is not, arbitrary tag bits are set using TBI.
 
-// This test is only valid for AArch64.
-// The linker must be explicitly specified when cross-compiling, so it is limited to
-// `aarch64-unknown-linux-gnu`.
 //@ only-aarch64-unknown-linux-gnu
+// Reason: this test is only valid for AArch64 with `gcc`. The linker must be explicitly specified
+// when cross-compiling, so it is limited to `aarch64-unknown-linux-gnu`.
 
-use run_make_support::{cc, dynamic_lib_name, extra_c_flags, run, rustc, target};
+use run_make_support::{dynamic_lib_name, extra_c_flags, gcc, run, rustc, target};
 
 fn main() {
     run_test("int");
@@ -29,7 +27,8 @@ fn run_test(variant: &str) {
         .target(target())
         .linker("aarch64-linux-gnu-gcc")
         .run();
-    cc().input(format!("bar_{variant}.c"))
+    gcc()
+        .input(format!("bar_{variant}.c"))
         .input(dynamic_lib_name("foo"))
         .out_exe("test")
         .args(&flags)