Fix dump_shaders for Vulkan backend in CMake build

Change-Id: I6670abe2fbc77418a5923643db0d377d38212288
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/118620
Reviewed-by: Austin Eng <enga@chromium.org>
Kokoro: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/dawn/native/CMakeLists.txt b/src/dawn/native/CMakeLists.txt
index d09103f..ca5d514 100644
--- a/src/dawn/native/CMakeLists.txt
+++ b/src/dawn/native/CMakeLists.txt
@@ -400,6 +400,7 @@
 endif()
 
 if (DAWN_ENABLE_OPENGL OR DAWN_ENABLE_VULKAN)
+    target_compile_definitions(dawn_native PRIVATE "DAWN_ENABLE_SPIRV_VALIDATION")
     target_sources(dawn_native PRIVATE
         "SpirvValidation.cpp"
         "SpirvValidation.h"