waf: git_submodule: support recursive submodules

Tools/ardupilotwaf/git_submodule.py

@@ -40,17 +40,18 @@ import os.path
 
 class update_submodule(Task.Task):
     color = 'BLUE'
-    run_str = '${GIT} -C ${SRC_ROOT} submodule update --init -- ${SUBMODULE_PATH}'
+    run_str = '${GIT} -C ${SRC_ROOT} submodule update --recursive --init -- ${SUBMODULE_PATH}'
 
     def runnable_status(self):
         e = self.env.get_flat
-        cmd = e('GIT'), '-C', e('SRC_ROOT'), 'submodule', 'status', '--', e('SUBMODULE_PATH')
+        cmd = e('GIT'), '-C', e('SRC_ROOT'), 'submodule', 'status', '--recursive', '--', e('SUBMODULE_PATH')
         out = self.generator.bld.cmd_and_log(cmd, quiet=Context.BOTH)
 
         # git submodule status uses a blank prefix for submodules that are up
         # to date
-        if out[0] != ' ':
-            return Task.RUN_ME
+        for line in out.splitlines():
+            if line[0] != ' ':
+                return Task.RUN_ME
 
         return Task.SKIP_ME