diff --git a/wscript b/wscript
index e252ab03fc..c78a0c854e 100644
--- a/wscript
+++ b/wscript
@@ -80,6 +80,7 @@ def configure(cfg):
     cfg.load('clang_compilation_database')
     cfg.load('waf_unit_test')
     cfg.load('mavgen')
+    cfg.load('git_submodule')
     cfg.load('gbenchmark')
     cfg.load('gtest')
     cfg.load('static_linking')
@@ -128,7 +129,7 @@ def _build_cmd_tweaks(bld):
             bld.fatal('check: gtest library is required')
         bld.add_post_fun(ardupilotwaf.test_summary)
 
-def _create_common_taskgens(bld):
+def _build_dynamic_sources(bld):
     bld(
         features='mavgen',
         source='modules/mavlink/message_definitions/v1.0/ardupilotmega.xml',
@@ -142,6 +143,7 @@ def _create_common_taskgens(bld):
         ],
     )
 
+def _build_common_taskgens(bld):
     # NOTE: Static library with vehicle set to UNKNOWN, shared by all
     # the tools and examples. This is the first step until the
     # dependency on the vehicles is reduced. Later we may consider
@@ -198,11 +200,23 @@ def _build_recursion(bld):
         bld.recurse(d)
 
 def build(bld):
+    bld.post_mode = Build.POST_LAZY
+
     bld.load('ardupilotwaf')
     bld.load('gtest')
 
     _build_cmd_tweaks(bld)
-    _create_common_taskgens(bld)
+
+    bld.add_group('git_submodules')
+    for name in bld.env.GIT_SUBMODULES:
+        bld.git_submodule(name)
+
+    bld.add_group('dynamic_sources')
+    _build_dynamic_sources(bld)
+
+    bld.add_group('build')
+    _build_common_taskgens(bld)
+
     _build_recursion(bld)
 
 ardupilotwaf.build_command('check',