Write python installation directories into registry to fix PyQt insta…

…llation

Inspired by qutebrowser's ci_install.py

scripts/install-qt.py

@@ -9,13 +9,30 @@
 
 
 if 'APPVEYOR' in os.environ:
+    def fix_registry(python_ver):
+        """Update install path on windows registry so PyQt installation installs at the correct
+        location.
+        python_ver must be "34", "27", etc.
+        """
+        import _winreg as winreg
+        python_dir = r'C:\Python%s' % python_ver
+        print("Fixing registry %s..." % python_ver)
+        assert os.path.isdir(python_dir)
+        registry_key = r'Software\Python\PythonCore\%s.%s' % (python_ver[0], python_ver[1])
+        with winreg.OpenKey(winreg.HKEY_CURRENT_USER,
+                            registry_key, 0,
+                            winreg.KEY_WRITE) as key:
+            winreg.SetValue(key, 'InstallPath', winreg.REG_SZ, python_dir)
+
     base_url = 'http://downloads.sourceforge.net/project/pyqt/'
     downloads = {
         'py34-pyqt5': 'PyQt5/PyQt-5.5/PyQt5-5.5-gpl-Py3.4-Qt5.5.0-x32.exe',
         'py34-pyqt4': 'PyQt4/PyQt-4.11.4/PyQt4-4.11.4-gpl-Py3.4-Qt4.8.7-x32.exe',
         'py27-pyqt4': 'PyQt4/PyQt-4.11.4/PyQt4-4.11.4-gpl-Py2.7-Qt4.8.7-x32.exe',
     }
     if 'INSTALL_QT' in os.environ:
+        fix_registry('34')
+        fix_registry('27')
         caption = os.environ['INSTALL_QT']
         url = downloads[caption]
         print("Downloading %s..." % caption)