Replace all gflag implementations with cvar implementations

src/xenia/gpu/vulkan/vulkan_gpu_flags.h

@@ -10,9 +10,8 @@
 #ifndef XENIA_GPU_VULKAN_VULKAN_GPU_FLAGS_H_
 #define XENIA_GPU_VULKAN_VULKAN_GPU_FLAGS_H_
 
-#include <gflags/gflags.h>
-
 #define FINE_GRAINED_DRAW_SCOPES 1
+#include "xenia/base/cvar.h"
 
 DECLARE_bool(vulkan_renderdoc_capture_all);
 DECLARE_bool(vulkan_native_msaa);