fix: Guard AppleSilicon GPU code behind __APPLE__ for cross-platform builds

- Wrap AppleSilicon::shutdown() call and declaration with #ifdef __APPLE__
  so Linux GPU builds don't get undefined reference errors
- Add IOReport library linking in CMakeLists.txt for macOS CMake builds

CMakeLists.txt

@@ -208,6 +208,12 @@ if(APPLE)
   target_link_libraries(libbtop
     $<LINK_LIBRARY:FRAMEWORK,CoreFoundation> $<LINK_LIBRARY:FRAMEWORK,IOKit>
   )
+  if(BTOP_GPU)
+    find_library(IOREPORT_LIB IOReport)
+    if(IOREPORT_LIB)
+      target_link_libraries(libbtop ${IOREPORT_LIB})
+    endif()
+  endif()
 elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" OR CMAKE_SYSTEM_NAME STREQUAL "MidnightBSD")
   # Avoid version mismatch for libstdc++ when a specific version of GCC is installed and not the
   # default one since all use the default ones RPATH

src/btop.cpp

@@ -231,7 +231,9 @@ void clean_quit(int sig) {
 #ifdef GPU_SUPPORT
 	Gpu::Nvml::shutdown();
 	Gpu::Rsmi::shutdown();
+	#ifdef __APPLE__
 	Gpu::AppleSilicon::shutdown();
+	#endif
 #endif
 
 

src/btop_shared.hpp

@@ -183,9 +183,11 @@ namespace Gpu {
 	namespace Rsmi {
 		extern bool shutdown();
 	}
+	#ifdef __APPLE__
 	namespace AppleSilicon {
 		extern bool shutdown();
 	}
+	#endif
 
 	//* Collect gpu stats and temperatures
     auto collect(bool no_update = false) -> vector<gpu_info>&;