[cpp] Suppress -Wextra-semi in third party code

Bug: 56257
Change-Id: I32565c14e5644c026c453851c10fe4c211430fe6
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/Vulkan-ValidationLayers/+/601843
Reviewed-by: Tamir Duberstein <tamird@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 0123470..ecb65f0 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -27,6 +27,7 @@
   cflags = [
     "-Wno-conversion",
     "-Wno-deprecated-copy",
+    "-Wno-extra-semi",
     "-Wno-implicit-fallthrough",
     "-Wno-missing-field-initializers",
     "-Wno-newline-eof",
@@ -59,6 +60,7 @@
 
   # Suppress warnings the vulkan code doesn't comply with.
   configs = [ "//build/config:Wno-unused-but-set-variable" ]
+  cflags = [ "-Wno-extra-semi" ]
 }
 
 # The validation layers
@@ -69,6 +71,7 @@
     "layers",
     "layers/generated",
   ]
+  cflags = [ "-Wno-extra-semi" ]
 }
 
 core_validation_sources = [