[PATCH vkd3d] tests: Make sure <stddef.h> is included.

[Chip Davis]

For cross-compiling, we can't assume that "vkd3d_windows.h" or
<windows.h> pulls in <stddef.h>. Fixes compilation errors related to
using offsetof(3).

Signed-off-by: Chip Davis 
---
 tests/d3d12_crosstest.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/d3d12_crosstest.h b/tests/d3d12_crosstest.h
index 7b59471..ff44324 100644
--- a/tests/d3d12_crosstest.h
+++ b/tests/d3d12_crosstest.h
@@ -50,6 +50,7 @@ typedef int HRESULT;
 #include <inttypes.h>
 #include <limits.h>
 #include <math.h>
+#include <stddef.h>
 #include <time.h>

#ifdef _WIN32