https://bugs.gentoo.org/show_bug.cgi?id=612860
By Tim Rakowski
We os.walk /usr with followlinks=True, but at least nodejs contains a "recursive" link in /usr/include/node

Index: catkin_pkg-0.3.1/src/catkin_pkg/packages.py
===================================================================
--- catkin_pkg-0.3.1.orig/src/catkin_pkg/packages.py
+++ catkin_pkg-0.3.1/src/catkin_pkg/packages.py
@@ -52,7 +52,9 @@ def find_package_paths(basepath, exclude_paths=None, exclude_subspaces=False):
     """
     paths = []
     real_exclude_paths = [os.path.realpath(p) for p in exclude_paths] if exclude_paths is not None else []
+    visited = set()
     for dirpath, dirnames, filenames in os.walk(basepath, followlinks=True):
+        visited.add(dirpath)
         if 'CATKIN_IGNORE' in filenames or \
             os.path.realpath(dirpath) in real_exclude_paths or \
                 (exclude_subspaces and '.catkin' in filenames):
@@ -63,7 +65,7 @@ def find_package_paths(basepath, exclude_paths=None, exclude_subspaces=False):
             del dirnames[:]
             continue
         for dirname in dirnames:
-            if dirname.startswith('.'):
+            if dirname.startswith('.') or os.path.realpath(os.path.join(dirpath, dirname)) in visited:
                 dirnames.remove(dirname)
     return paths