As discovered in bpo-41509, relpath can strip spaces, so match that expectation.

1 files changed, 1 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index 37953051..5d98c029 100755
--- a/setup.py
+++ b/setup.py
@@ -117,7 +117,7 @@ class install_with_pth(install):
         """
         suffix = os.path.relpath(self.install_lib, self.install_libbase)
 
-        if suffix == self._pth_contents:
+        if suffix.strip() == self._pth_contents.strip():
             self.install_lib = self.install_libbase