diff --git a/gtsam/3rdparty/GeographicLib/CMakeLists.txt b/gtsam/3rdparty/GeographicLib/CMakeLists.txt
index 422791e17..a72a06bf1 100644
--- a/gtsam/3rdparty/GeographicLib/CMakeLists.txt
+++ b/gtsam/3rdparty/GeographicLib/CMakeLists.txt
@@ -109,15 +109,15 @@ endif ()
 set_property (CACHE GEOGRAPHICLIB_LIB_TYPE
   PROPERTY STRINGS "SHARED" "STATIC" "BOTH")
 
-if (GEOGRAPHICLIB_LIB_TYPE STREQUAL "BOTH")
+if ("${GEOGRAPHICLIB_LIB_TYPE}" STREQUAL "BOTH")
   set (GEOGRAPHICLIB_SHARED_LIB ON)
   set (GEOGRAPHICLIB_STATIC_LIB ON)
   set (GEOGRAPHICLIB_LIB_TYPE_VAL 2)
-elseif (GEOGRAPHICLIB_LIB_TYPE STREQUAL "SHARED")
+elseif ("${GEOGRAPHICLIB_LIB_TYPE}" STREQUAL "SHARED")
   set (GEOGRAPHICLIB_SHARED_LIB ON)
   set (GEOGRAPHICLIB_STATIC_LIB OFF)
   set (GEOGRAPHICLIB_LIB_TYPE_VAL 1)
-elseif (GEOGRAPHICLIB_LIB_TYPE STREQUAL "STATIC")
+elseif ("${GEOGRAPHICLIB_LIB_TYPE}" STREQUAL "STATIC")
   set (GEOGRAPHICLIB_SHARED_LIB OFF)
   set (GEOGRAPHICLIB_STATIC_LIB ON)
   set (GEOGRAPHICLIB_LIB_TYPE_VAL 0)