CMake: Add options to use -fsanitize={address,undefined}

To make bugs like #485, #486, #487 and #488 easier to find in future.

CMakeLists.txt

@@ -1,8 +1,10 @@
 cmake_minimum_required(VERSION 3.0)
 
 # Config options
-set(BUILD_EXAMPLES ON CACHE BOOL "Build the examples.")
-set(BUILD_GAMES ON CACHE BOOL "Build the example games.")
+option(BUILD_EXAMPLES "Build the examples." ON)
+option(BUILD_GAMES "Build the example games." ON)
+option(ENABLE_ASAN  "Enable AddressSanitizer (ASAN) for debugging (degrades performance)" OFF)
+option(ENABLE_UBSAN "Enable UndefinedBehaviorSanitizer (UBSan) for debugging" OFF)
 
 if(CMAKE_VERSION VERSION_LESS "3.1")
   if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
@@ -11,17 +13,31 @@ if(CMAKE_VERSION VERSION_LESS "3.1")
 else()
   set (CMAKE_C_STANDARD 99)
 endif()
+
 include(CheckCCompilerFlag)
-foreach(option -Werror=pointer-arith;-Werror=implicit-function-declaration)
-    CHECK_C_COMPILER_FLAG("${option}" COMPILER_HAS_THOSE_TOGGLES)
+function(add_if_flag_works flag)
+    CHECK_C_COMPILER_FLAG("${flag}" COMPILER_HAS_THOSE_TOGGLES)
     set(outcome "Failed")
     if(COMPILER_HAS_THOSE_TOGGLES)
-        set(CMAKE_C_FLAGS "${option} ${CMAKE_C_FLAGS}")
+        foreach(var ${ARGN})
+            set(${var} "${flag} ${${var}}" PARENT_SCOPE)
+        endforeach()
         set(outcome "works")
     endif()
-    message(STATUS "Testing if ${option} can be used -- ${outcome}")
-endforeach()
+    message(STATUS "Testing if ${flag} can be used -- ${outcome}")
+endfunction()
 
+add_if_flag_works(-Werror=pointer-arith CMAKE_C_FLAGS)
+add_if_flag_works(-Werror=implicit-function-declaration CMAKE_C_FLAGS)
+
+if (ENABLE_ASAN)
+    add_if_flag_works(-fno-omit-frame-pointer CMAKE_C_FLAGS CMAKE_LINKER_FLAGS)
+    add_if_flag_works(-fsanitize=address CMAKE_C_FLAGS CMAKE_LINKER_FLAGS)
+endif()
+if (ENABLE_UBSAN)
+    add_if_flag_works(-fno-omit-frame-pointer CMAKE_C_FLAGS CMAKE_LINKER_FLAGS)
+    add_if_flag_works(-fsanitize=undefined CMAKE_C_FLAGS CMAKE_LINKER_FLAGS)
+endif()
 
 add_subdirectory(src release)
 
@@ -32,4 +48,3 @@ endif()
 if (${BUILD_GAMES})
   add_subdirectory(games)
 endif()
-

src/CMakeLists.txt

@@ -8,11 +8,11 @@ set(RAYLIB raylib)    # Name of the generated library
 
 ### Config options ###
 # Shared library is always PIC. Static library should be PIC too if linked into a shared library
-set(WITH_PIC      OFF CACHE BOOL "Compile static library as position-independent code" OFF)
+option(WITH_PIC "Compile static library as position-independent code" OFF)
 # Build a static and/or shared raylib?
-set(SHARED ">OFF CACHE BOOL "Build raylib as a dynamic library")
-set(STATIC ">ON  CACHE BOOL "Build raylib as a static library")
-set(MACOS_FATLIB  ">ON  CACHE BOOL "Build fat library for both i386 and x86_64 on macOS")
+option(SHARED "Build raylib as a dynamic library" OFF)
+option(STATIC "Build raylib as a static library" ON)
+option(MACOS_FATLIB  "Build fat library for both i386 and x86_64 on macOS" ON)
 
 if(NOT (STATIC OR SHARED))
   message(FATAL_ERROR "Nothing to do if both -DSHARED=OFF and -DSTATIC=OFF...")