diff --git a/deps/ox/CMakeLists.txt b/deps/ox/CMakeLists.txt
index e7bd79f1..c15f60e0 100644
--- a/deps/ox/CMakeLists.txt
+++ b/deps/ox/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.13)
 
 project(Ox)
 
@@ -6,10 +6,10 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
 include(address_sanitizer)
 
 if(NOT DEFINED OX_RUN_TESTS)
-	set(OX_RUN_TESTS "ON")
+	set(OX_RUN_TESTS ON)
 endif()
-if(NOT DEFINED OX_RUN_TESTS)
-	set(OX_RUN_TESTS "ON")
+if(NOT DEFINED OX_BUILD_EXEC)
+	set(OX_BUILD_EXEC ON)
 endif()
 if(NOT DEFINED OX_USE_STDLIB)
 	set(OX_USE_STDLIB ON)
@@ -18,13 +18,13 @@ if(NOT DEFINED OX_BARE_METAL)
 	set(OX_BARE_METAL OFF)
 endif()
 
-set(OX_RUN_TESTS ${OX_RUN_TESTS} CACHE STRING "Run tests (ON/OFF)")
-set(OX_RUN_TESTS ${OX_RUN_TESTS} CACHE STRING "Run tests (ON/OFF)")
-set(OX_USE_STDLIB ${OX_USE_STDLIB} CACHE STRING "Build libraries that need the std lib (ON/OFF)")
-set(OX_BARE_METAL ${OX_BARE_METAL} CACHE STRING "Bare metal build (TRUE/FALSE)")
+set(OX_RUN_TESTS ${OX_RUN_TESTS} CACHE BOOL "Run tests (ON/OFF)")
+set(OX_BUILD_EXEC ${OX_BUILD_EXEC} CACHE BOOL "Build executables (ON/OFF)")
+set(OX_USE_STDLIB ${OX_USE_STDLIB} CACHE BOOL "Build libraries that need the std lib (ON/OFF)")
+set(OX_BARE_METAL ${OX_BARE_METAL} CACHE BOOL "Bare metal build (TRUE/FALSE)")
 
 # can't run tests without building them
-if(OX_BUILD_EXEC STREQUAL "OFF" OR NOT ${OX_USE_STDLIB})
+if(NOT OX_BUILD_EXEC OR NOT OX_USE_STDLIB)
 	set(OX_BUILD_EXEC OFF)
 	set(OX_RUN_TESTS OFF)
 endif()
@@ -39,7 +39,7 @@ else()
 	add_definitions(-DDEBUG)
 endif()
 
-if(NOT ${OX_USE_STDLIB})
+if(NOT OX_USE_STDLIB)
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostdlib")
 endif()
 
@@ -55,6 +55,7 @@ if(NOT MSVC)
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast")
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Woverloaded-virtual")
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wpedantic")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshadow")
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare")
 	#set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-conversion")
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wunused")