fix(cmake): Correct macOS KEXT build using absolute SDK paths

The KEXT (PcmMsrDriver) build failed on macOS because it could not
find kernel headers like `<IOKit/IOLib.h>`. This was caused by CMake
incorrectly resolving include paths to `/System/Library/...` instead of
the correct path inside the macOS SDK.

This commit fixes the issue by localizing the solution to the KEXT's
`CMakeLists.txt`. It now dynamically detects the active macOS SDK path
using `xcrun` and uses it to construct absolute include paths for the
KEXT target only.

This ensures the KEXT can find its required kernel headers without
affecting other user-space targets that may depend on libraries from
standard locations like Homebrew.

Close: #928

Author: darren

src/MacMSRDriver/PcmMsr/CMakeLists.txt

@@ -11,10 +11,20 @@ add_executable(
 
 set_target_properties(PcmMsrDriver PROPERTIES BUNDLE_EXTENSION kext MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/PcmMsr-Info.plist)
 
+# For KEXT compilation on macOS, we must explicitly point to the Kernel frameworks within the SDK.
+if(APPLE)
+    # Find the active macOS SDK path
+    execute_process(
+        COMMAND xcrun --sdk macosx --show-sdk-path
+        OUTPUT_VARIABLE MACOSX_SDK_PATH
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    message(STATUS "Using SDK for KEXT: ${MACOSX_SDK_PATH}")
+endif()
 
 target_include_directories(PcmMsrDriver PRIVATE
-        ${CMAKE_OSX_SYSROOT}/System/Library/Frameworks/Kernel.framework/PrivateHeaders
-        ${CMAKE_OSX_SYSROOT}/System/Library/Frameworks/Kernel.framework/Headers
+        "${MACOSX_SDK_PATH}/System/Library/Frameworks/Kernel.framework/PrivateHeaders"
+        "${MACOSX_SDK_PATH}/System/Library/Frameworks/Kernel.framework/Headers"
 )
 target_compile_definitions(PcmMsrDriver PRIVATE
         -DKERNEL