Set user if it is not set.

README.md

@@ -51,6 +51,7 @@ issues (or lack of support for a particular ecosystem), please file a bug.
 - ninja, including ninja file generators:
     - meson
 - Node
+- Octave
 - Perl
     - Module::Build::Tiny
 - PHP Pear

ognibuild/resolver/__init__.py

@@ -71,6 +71,8 @@ class CPANResolver(Resolver):
 
         if not self.user_local:
             user = "root"
+        else:
+            user = None
 
         missing = []
         for requirement in requirements: