Add copts to suppress third-party warnings

Change-Id: I8f98b783397d35c810754153d2317baefd16cbc9
Bug: b/274013040
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/658018
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/third_party/vulkanmemoryallocator/BUILD.bazel b/third_party/vulkanmemoryallocator/BUILD.bazel
index 1593e7f..c0e035b 100644
--- a/third_party/vulkanmemoryallocator/BUILD.bazel
+++ b/third_party/vulkanmemoryallocator/BUILD.bazel
@@ -9,6 +9,15 @@
     srcs = [
         "GrVulkanMemoryAllocator.cpp",
     ],
+    copts = [
+        # Because `copts` options don't propagate up the stack, some static errors in
+        # `vk_mem_alloc.h` need to be suppressed in the BUILD rule which includes the library.
+        #
+        # https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator/issues/298
+        "-Wno-unused-variable",
+        # https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator/issues/299
+        "-Wno-implicit-fallthrough",
+    ],
     includes = [
         ".",
     ],