From ba09d5d676f5b536e7edc5bcbe1d5a8f8393771b Mon Sep 17 00:00:00 2001
From: chrisbeall <chrisbeall@gmail.com>
Date: Sat, 18 May 2019 20:52:21 -0700
Subject: [PATCH] Fix GeographicLib configuration when
 GTSAM_INSTALL_GEOGRAPHICLIB is toggled from ON to OFF, or when
 system-installed copy disappears.

---
 gtsam/3rdparty/CMakeLists.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gtsam/3rdparty/CMakeLists.txt b/gtsam/3rdparty/CMakeLists.txt
index 6ca7514ac..9a99bdba8 100644
--- a/gtsam/3rdparty/CMakeLists.txt
+++ b/gtsam/3rdparty/CMakeLists.txt
@@ -41,6 +41,10 @@ add_subdirectory(ceres)
 # add_subdirectory (tools)
 
 # Find GeographicLib using the find script distributed with it
+unset(GEOGRAPHICLIB_FOUND CACHE)
+unset(GeographicLib_INCLUDE_DIRS CACHE)
+unset(GeographicLib_LIBRARIES CACHE)
+unset(GeographicLib_LIBRARY_DIRS CACHE)
 include(GeographicLib/cmake/FindGeographicLib.cmake)
 
 # Set up the option to install GeographicLib