Cleanup.

src/hmd_openvr.cpp

@@ -4,6 +4,8 @@
  */
 
 #include "hmd_openvr.h"
+
+BX_PRAGMA_DIAGNOSTIC_IGNORED_CLANG_GCC("-Wunused-variable")
 #include <openvr/openvr_capi.h>
 
 namespace bgfx