appveyor: add error handler to fix shutil.rmtree on Windows

appveyor-test.py

@@ -165,7 +165,7 @@ class TestAddDependency(unittest.TestCase):
     def setUp(self):
         os.environ['SETUP_PATH'] = '.:appveyor'
         if os.path.exists(self.location):
-            shutil.rmtree(self.location)
+            shutil.rmtree(self.location, onerror=do.remove_readonly)
         do.clear_lists()
         os.chdir(builddir)
         do.source_set('defaults')

appveyor/do.py

@@ -4,7 +4,8 @@
 
 from __future__ import print_function
 
-import sys, os, shutil, fileinput
+import sys, os, stat, shutil
+import fileinput
 import logging
 import subprocess as sp
 import distutils.util
@@ -37,6 +38,11 @@ def clear_lists():
     del modules_to_compile[:]
     setup.clear()
 
+# Error-handler to make shutil.rmtree delete read-only files on Windows
+def remove_readonly(func, path, excinfo):
+    os.chmod(path, stat.S_IWRITE)
+    func(path)
+
 # source_set(setup)
 #
 # Source a settings file (extension .set) found in the setup_dirs path
@@ -190,7 +196,7 @@ def add_dependency(dep, tag):
         logger.debug('Found checked_out commit %s, git head is %s', checked_out, head)
         if head != checked_out:
             logger.debug('Dependency %s out of date - removing', dep)
-            shutil.rmtree(place)
+            shutil.rmtree(place, onerror=remove_readonly)
         else:
             print('Found {0} of dependency {1} up-to-date in {2}'.format(tag, dep, place))