Add use_asan option for MSVC to enable AddressSanitizer

Exposes AddressSanitizer support in MSVC compiler. Can be installed via individual
components in the Visual Studio 2019 Installer.

Disabled by default. Compile the engine with `scons use_asan=yes`.

platform/windows/detect.py

@@ -72,6 +72,7 @@ def get_opts():
         BoolVariable("use_llvm", "Use the LLVM compiler", False),
         BoolVariable("use_thinlto", "Use ThinLTO", False),
         BoolVariable("use_static_cpp", "Link MinGW/MSVC C++ runtime libraries statically", True),
+        BoolVariable("use_asan", "Use address sanitizer (ASAN)", False),
     ]
 
 
@@ -306,6 +307,12 @@ def configure_msvc(env, manual_msvc_config):
         env.Prepend(CPPPATH=[p for p in os.getenv("INCLUDE").split(";")])
         env.Append(LIBPATH=[p for p in os.getenv("LIB").split(";")])
 
+    # Sanitizers
+    if env["use_asan"]:
+        env.extra_suffix += ".s"
+        env.Append(LINKFLAGS=["/INFERASANLIBS"])
+        env.Append(CCFLAGS=["/fsanitize=address"])
+
     # Incremental linking fix
     env["BUILDERS"]["ProgramOriginal"] = env["BUILDERS"]["Program"]
     env["BUILDERS"]["Program"] = methods.precious_program