Don't set VULKAN_HPP_NO_NODISCARD_WARNINGS

Setting VULKAN_HPP_NO_NODISCARD_WARNINGS globally is a divergence from
upstream and removes a potentially-valuable check. Clients should be
updated to set VULKAN_HPP_NO_NODISCARD_WARNINGS if needed.

Change-Id: Iec84ef2ed3ce84a298a22418a04b10e4fa8ff046
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/Vulkan-Headers/+/750990
Fuchsia-Auto-Submit: John Bauman <jbauman@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Reviewed-by: John Rosasco <rosasco@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 41c058d..ca71f99 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -46,10 +46,6 @@
   }
 }
 
-config("no_nodiscard_warnings") {
-  defines = [ "VULKAN_HPP_NO_NODISCARD_WARNINGS" ]
-}
-
 # Vulkan headers only, no compiled sources.
 source_set("vulkan_headers") {
   sources = [
@@ -64,7 +60,6 @@
   ]
   public_configs = [
     ":vulkan_headers_config",
-    ":no_nodiscard_warnings",
   ]
   if (defined(vulkan_use_wayland) && vulkan_use_wayland) {
     public_deps = [ "//third_party/wayland:client" ]