waf: reconfigure for any changes in loaded modules

Waf's autoconfig feature works only for wscripts loaded by the recurse()
function. This patch extends that functionality to all loaded modules, which
includes Waf tools.

wscript

@@ -82,6 +82,23 @@ revisions.
         default=False,
         help='Configure as debug variant.')
 
+def _collect_autoconfig_files(cfg):
+    for m in sys.modules.values():
+        paths = []
+        if hasattr(m, '__file__'):
+            paths.append(m.__file__)
+        elif hasattr(m, '__path__'):
+            for p in m.__path__:
+                paths.append(p)
+
+        for p in paths:
+            if p in cfg.files or not os.path.isfile(p):
+                continue
+
+            with open(p, 'rb') as f:
+                cfg.hash = Utils.h_list((cfg.hash, f.read()))
+                cfg.files.append(p)
+
 def configure(cfg):
     cfg.env.BOARD = cfg.options.board
     cfg.env.DEBUG = cfg.options.debug
@@ -142,6 +159,8 @@ def configure(cfg):
 
     cfg.write_config_header(os.path.join(cfg.variant, 'ap_config.h'))
 
+    _collect_autoconfig_files(cfg)
+
 def collect_dirs_to_recurse(bld, globs, **kw):
     dirs = []
     globs = Utils.to_list(globs)