[MKISOFS] Fix Clang check for macOS platforms (reactos#7037)

* [MKISOFS] Fix Clang check for macOS platforms

On macOS, CMAKE_C_COMPILER_ID is "AppleClang". While certainly Clang,
this does not match the exact string "Clang" that is being checked for,
and as a result the warning flags guarded thereby are not passed to the
compiler. With this change CMake will recognize both Clang and AppleClang.

* Update sdk/tools/mkisofs/CMakeLists.txt

Author: wjk

sdk/tools/mkisofs/CMakeLists.txt

@@ -107,7 +107,8 @@ else()
     # Silence compilers checking for invalid formatting sequences.
     target_compile_options(libschily PRIVATE "-Wno-format")
 
-    if(CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL "15")
+    # MATCHES must be used here because on macOS, CMake uses the compiler ID "AppleClang".
+    if(CMAKE_C_COMPILER_ID MATCHES "Clang$" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL "15")
         # mkisofs uses K&R-style function definitions to support very old compilers.
         # This causes warnings with modern compilers.
         target_compile_options(libmdigest PRIVATE "-Wno-deprecated-non-prototype")