diff --git a/extern/libmv/third_party/ceres/CMakeLists.txt b/extern/libmv/third_party/ceres/CMakeLists.txt
index 16b7f12fb33..2fd8c748817 100644
--- a/extern/libmv/third_party/ceres/CMakeLists.txt
+++ b/extern/libmv/third_party/ceres/CMakeLists.txt
@@ -250,7 +250,7 @@ else()
 endif()
 
 if(APPLE)
-	if( STREQUAL "10.5")
+	if(CMAKE_OSX_DEPLOYMENT_TARGET STREQUAL "10.5")
 		add_definitions(
 			-DCERES_NO_TR1
 		)