macOS/iOS fixes plus other generic fixes for clang and validation warnings (#1117)

* Fix clang Objective-C++ flags for macOS command line builds

* Fix getAssetPath() and getShaderBasePath() for macOS command line builds

* Protect debugUtilsMessageCallback() from failing when pMessageIdName is NULL

* Fix a few clang function override and mismatched type warnings

* Fix validation layer warnings on exit for computeraytracing example

* Fix regression in text visibility toggle for textOverlay example

* Support VK_USE_PLATFORM_METAL_EXT vs. deprecated VK_USE_PLATFORM_MACOS_MVK / DVK_USE_PLATFORM_IOS_MVK

* Check dynamic state features before enabling capabilities in dynamicstate example

* Fix vkCmdDraw() vertexCount argument (PARTICLE_COUNT) in particlesystem example

* Update examples list and restore benchmarking script (to top level)

* Fix validation warning in descriptorindexing example

* Fix device max recursion depth validation warnings in ray tracing examples

* Fix OpenMP build settings for texture3d example on all platforms

* Update and simplify build instructions for macOS

* Update CI script with correct library path for libomp on macOS x86_64

* Update CI scipt to install libomp prior to macOS builds

* Trying one more time to get the CI script working for macOS libomp

* Fix vertexCount argument using calculated size in particlesystem example

* Fix combined image descriptor offset calculation in descriptorbuffer example

* macOS: Support non-system level Vulkan SDK installs, with fallback to MoltenVK library

base/CommandLineParser.hpp

@@ -105,7 +105,7 @@ public:
 		std::string value = options[name].value;
 		if (value != "") {
 			char* numConvPtr;
-			int32_t intVal = strtol(value.c_str(), &numConvPtr, 10);
+			int32_t intVal = (int32_t)strtol(value.c_str(), &numConvPtr, 10);
 			return (intVal > 0) ? intVal : defaultValue;
 		}
 		else {