byte-unixbench: respect compiler choice (#39242)

Co-authored-by: Harmen Stoppels <harmenstoppels@gmail.com>

var/spack/repos/builtin/packages/byte-unixbench/package.py

@@ -16,6 +16,10 @@ class ByteUnixbench(MakefilePackage):
 
     build_directory = "UnixBench"
 
+    @property
+    def build_targets(self):
+        return [f"CC={spack_cc}"]
+
     def install(self, spec, prefix):
         with working_dir(self.build_directory):
             install_tree(".", prefix)