fix(macos): macOS build fixes and MoltenVK improvements

- Switch to Ryujinx MoltenVK build compiled with older Metal SDK to avoid
  MSL 3.2 thread_scope_subgroup bugs that cause text rendering issues
- Exclude Apple from GNU ld.bfd linker option (macOS uses different linker)
- Handle VK_ERROR_FRAGMENTED_POOL in Vulkan descriptor pool allocation

src/video_core/vulkan_common/vulkan_wrapper.cpp

@@ -565,6 +565,7 @@ DescriptorSets DescriptorPool::Allocate(const VkDescriptorSetAllocateInfo& ai) c
     case VK_SUCCESS:
         return DescriptorSets(std::move(sets), num, owner, handle, *dld);
     case VK_ERROR_OUT_OF_POOL_MEMORY:
+    case VK_ERROR_FRAGMENTED_POOL:
         return {};
     default:
         throw Exception(result);