Auto merge of #109751 - bzEq:aix-gmake, r=Mark-Simulacrum

AIX uses gmake for GNU style Makefile

AIX's `make` is SystemV style, should use `gmake` for GNU style Makefile.

Author: bors

src/tools/compiletest/src/runtest.rs

@@ -2999,6 +2999,7 @@ impl<'test> TestCx<'test> {
             || host.contains("freebsd")
             || host.contains("netbsd")
             || host.contains("openbsd")
+            || host.contains("aix")
         {
             "gmake"
         } else {