Cleanup main CMakeLists.txt to better match CMake conventions

deps/ox/CMakeLists.txt

@@ -11,52 +11,42 @@ set(OX_USE_STDLIB "ON" CACHE STRING "Build libraries that need the std lib (ON/O
 
 # can't run tests without building them
 if(OX_BUILD_EXEC STREQUAL "OFF" OR OX_USE_STDLIB STREQUAL "OFF")
-	set(OX_BUILD_EXEC "OFF")
-	set(OX_RUN_TESTS "OFF")
+	set(OX_BUILD_EXEC OFF)
+	set(OX_RUN_TESTS OFF)
 endif()
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
+if (CMAKE_BUILD_TYPE STREQUAL "Release")
+	add_definitions(-DNDEBUG)
+else()
+	add_definitions(-DDEBUG)
+endif()
+
 if(OX_USE_STDLIB STREQUAL "ON")
 	add_definitions(-DOX_USE_STDLIB)
+else()
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostdlib")
 endif()
 
 if(NOT MSVC)
-	add_definitions(
-		-std=c++17
-		-nostdlib
-		-fno-exceptions
-		-fno-rtti
-		-Wall
-		-Wextra
-		-Wsign-compare
-		-Wunused-variable
-	)
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wunused-variable")
+
 	if (CMAKE_BUILD_TYPE STREQUAL "Release")
-		add_definitions(
-			-Werror
-			-O3
-		)
+		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
 	endif()
 	if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-		add_definitions(
-			-fdiagnostics-color # forces colored output when using ninja
-		)
+		# forces colored output when using ninja
+		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdiagnostics-color")
 	endif()
 endif()
 
-if (CMAKE_BUILD_TYPE STREQUAL "Release")
-	add_definitions(
-		-DNDEBUG
-	)
-else()
-	add_definitions(
-		-DDEBUG
-	)
-endif()
-
 enable_testing()
 
 include_directories("src")