Merge with head.

--HG--
extra : convert_revision : e4be9d5f2ce8e3252958e2c5e03710b0bf9755c7

src/SConscript

@@ -151,7 +151,6 @@ env.Append(CPPDEFINES=[('THE_ISA','%s_ISA' % env['TARGET_ISA'].upper())])
 #
 # Walk the tree and execute all SConscripts
 #
-scripts = []
 srcdir = env['SRCDIR']
 for root, dirs, files in os.walk(srcdir, topdown=True):
     if root == srcdir:
@@ -164,6 +163,15 @@ for root, dirs, files in os.walk(srcdir, topdown=True):
         base = root[len(srcdir) + 1:]
         SConscript(joinpath(base, 'SConscript'))
 
+for extra in env['EXTRAS'].split(':'):
+    extra = os.path.expanduser(extra)
+    env.Append(CPPPATH=[Dir(extra)])
+    for root, dirs, files in os.walk(extra, topdown=True):
+        if 'SConscript' in files:
+            subdir = root[len(os.path.dirname(extra))+1:]
+            build_dir = joinpath(env['BUILDDIR'], subdir)
+            SConscript(joinpath(root, 'SConscript'), build_dir=build_dir)
+
 for opt in env.ExportOptions:
     env.ConfigFile(opt)