Fixed 'select_scheme()' so it doesn't override a directory attribute that's
already been set (eg. by a command-line option).
diff --git a/Lib/distutils/command/install.py b/Lib/distutils/command/install.py
index 4e68e00..ba4110c 100644
--- a/Lib/distutils/command/install.py
+++ b/Lib/distutils/command/install.py
@@ -356,7 +356,9 @@
# it's the caller's problem if they supply a bad name!
scheme = INSTALL_SCHEMES[name]
for key in ('purelib', 'platlib', 'scripts', 'data'):
- setattr (self, 'install_' + key, scheme[key])
+ attrname = 'install_' + key
+ if getattr(self, attrname) is None:
+ setattr(self, attrname, scheme[key])
def _expand_attrs (self, attrs):