[cmake] only use MoltenVk on Apple platforms

Signed-off-by: lizzie <lizzie@eden-emu.dev>

externals/CMakeLists.txt

@@ -393,16 +393,18 @@ if (ANDROID)
     add_library(oboe::oboe ALIAS oboe)
 endif()
 
-# moltenvk
-if (NOT YUZU_USE_BUNDLED_MOLTENVK)
-    find_library(MOLTENVK_LIBRARY MoltenVK)
-else()
-    unset(MOLTENVK_LIBRARY)
-endif()
+if (APPLE)
+    # moltenvk
+    if (NOT YUZU_USE_BUNDLED_MOLTENVK)
+        find_library(MOLTENVK_LIBRARY MoltenVK)
+    else()
+        unset(MOLTENVK_LIBRARY)
+    endif()
 
-# TODO: kosmickrisp?
-if (NOT MOLTENVK_LIBRARY)
-    AddJsonPackage(moltenvk)
+    # TODO: kosmickrisp?
+    if (NOT MOLTENVK_LIBRARY)
+        AddJsonPackage(moltenvk)
 
-    set(MOLTENVK_LIBRARY "${moltenvk_SOURCE_DIR}/MoltenVK/dylib/macOS/libMoltenVK.dylib" CACHE STRING "" FORCE)
+        set(MOLTENVK_LIBRARY "${moltenvk_SOURCE_DIR}/MoltenVK/dylib/macOS/libMoltenVK.dylib" CACHE STRING "" FORCE)
+    endif()
 endif()