Fix tests on Windows

tests/catalog/get_test.py

         }
     })
 
+    dds.scope.enter_context(ensure_dir(dds.source_root))
     dds.repo_add(http_repo.url)
     dds.catalog_get('neo-sqlite3@0.3.0')
     assert (dds.scratch_dir / 'neo-sqlite3@0.3.0').is_dir()

tests/http.py

     the given TCP port.
     """
     handler = partial(DirectoryServingHTTPRequestHandler, dir=dirpath)
-    addr = ('localhost', port)
+    addr = ('127.0.0.1', port)
     pool = ThreadPoolExecutor()
     with HTTPServer(addr, handler) as httpd:
         pool.submit(lambda: httpd.serve_forever(poll_interval=0.1))
         try:
-            yield ServerInfo(f'http://localhost:{port}', dirpath)
+            print('Serving at', addr)
+            yield ServerInfo(f'http://127.0.0.1:{port}', dirpath)
         finally:
             httpd.shutdown()
 
         Import some packages into the repo for the given JSON data. Uses
         mkrepo.py
         """
-        with tempfile.NamedTemporaryFile() as f:
+        with tempfile.NamedTemporaryFile(delete=False) as f:
             f.write(json.dumps(data).encode())
-            f.flush()
+            f.close()
             self.import_json_file(Path(f.name))
+            Path(f.name).unlink()
 
     def import_json_file(self, fpath: Path) -> None:
         """

tests/msvc.tc.jsonc

 {
     "$schema": "../res/toolchain-schema.json",
-    "compiler_id": "msvc"
+    "compiler_id": "msvc",
+    "cxx_flags": "/std:c++latest"
 }

tools/mkrepo.py

 import os
 import re
 import shutil
+import stat
 import sys
 import tarfile
 import tempfile
         if not self.only_matching:
             # Remove everything
             if abspath.is_dir():
-                shutil.rmtree(abspath)
+                better_rmtree(abspath)
             else:
                 abspath.unlink()
             return
             items = glob_if_exists(abspath, pat)
             for f in items:
                 if f.is_dir():
-                    shutil.rmtree(f)
+                    better_rmtree(f)
                 else:
                     f.unlink()
 
             check_call(['git', 'clone', '--quiet', self.url, f'--depth=1', f'--branch={self.ref}', str(tdir)])
             yield tdir
         finally:
-            shutil.rmtree(tdir)
+            better_rmtree(tdir)
 
 
 class ForeignPackage(NamedTuple):
             yield SpecPackage.parse_data(name, version, defin)
 
 
+def _on_rm_error_win32(fn, filepath, _exc_info):
+    p = Path(filepath)
+    p.chmod(stat.S_IWRITE)
+    p.unlink()
+
+
+def better_rmtree(dir: Path) -> None:
+    if os.name == 'nt':
+        shutil.rmtree(dir, onerror=_on_rm_error_win32)
+    else:
+        shutil.rmtree(dir)
+
+
 @contextmanager
 def http_dl_unpack(url: str) -> Iterator[Path]:
     req = request.urlopen(url)
         subdir = next(iter(Path(tdir).iterdir()))
         yield subdir
     finally:
-        shutil.rmtree(tdir)
+        better_rmtree(tdir)
 
 
 @contextmanager