docker: extend "cc" command to accept compiler

When calling our cross-compilation images we want to call something
other than the default cc.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Fam Zheng <famz@redhat.com>

tests/docker/docker.py

@@ -419,6 +419,8 @@ class CcCommand(SubCommand):
     def args(self, parser):
         parser.add_argument("--image", "-i", required=True,
                             help="The docker image in which to run cc")
+        parser.add_argument("--cc", default="cc",
+                            help="The compiler executable to call")
         parser.add_argument("--source-path", "-s", nargs="*", dest="paths",
                             help="""Extra paths to (ro) mount into container for
                             reading sources""")
@@ -432,7 +434,7 @@ class CcCommand(SubCommand):
         if args.paths:
             for p in args.paths:
                 cmd += ["-v", "%s:%s:ro,z" % (p, p)]
-        cmd += [args.image, "cc"]
+        cmd += [args.image, args.cc]
         cmd += argv
         return Docker().command("run", cmd, args.quiet)