use new tie breaker.

ognibuild/debian/build_deps.py

@@ -50,8 +50,13 @@ class BuildDependencyTieBreaker(object):
             self._counts = self._count()
         by_count = {}
         for req in reqs:
-            by_count[req] = self._counts.get(list(req.package_names())[0])
-        return max(by_count.items(), key=lambda k: k[1] or 0)[0]
+            try:
+                by_count[req] = self._counts[list(req.package_names())[0]]
+            except KeyError:
+                pass
+        if not by_count:
+            return None
+        return max(by_count.items(), key=lambda k: k[1])[0]
 
 
 if __name__ == '__main__':

ognibuild/debian/fix_build.py

@@ -444,8 +444,10 @@ def versioned_package_fixers(session, packaging_context):
 def apt_fixers(apt, packaging_context) -> List[BuildFixer]:
     from ..resolver.apt import AptResolver
     from .udd import udd_tie_breaker
+    from .build_deps import BuildDependencyTieBreaker
     apt_tie_breakers = [
         partial(python_tie_breaker, packaging_context.tree, packaging_context.subpath),
+        BuildDependencyTieBreaker.from_session(apt.sesion),
         udd_tie_breaker,
         ]
     resolver = AptResolver(apt, apt_tie_breakers)