From ef8026bc239b39c1d50e20e18d57dd2f77637f5e Mon Sep 17 00:00:00 2001
From: Fan Jiang <i@fanjiang.me>
Date: Mon, 6 Jan 2020 22:35:11 -0500
Subject: [PATCH] Regression

---
 cmake/GtsamCythonWrap.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/GtsamCythonWrap.cmake b/cmake/GtsamCythonWrap.cmake
index 51ef4ab92..93dd2e32d 100644
--- a/cmake/GtsamCythonWrap.cmake
+++ b/cmake/GtsamCythonWrap.cmake
@@ -8,7 +8,7 @@ unset(PYTHON_MAJOR_VERSION CACHE)
 unset(PYTHON_LIBRARY CACHE)
 
 # Allow override from command line
-if(NOT PYTHON_LIBRARY)
+if(NOT DEFINED PYTHON_LIBRARY)
   if(GTSAM_PYTHON_VERSION STREQUAL "Default")
     find_package(PythonInterp REQUIRED)
     find_package(PythonLibs REQUIRED)