anv: Add extern "C" guards

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16970>

src/intel/vulkan/anv_private.h

@@ -86,6 +86,10 @@
 #include "vk_queue.h"
 #include "vk_log.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Pre-declarations needed for WSI entrypoints */
 struct wl_surface;
 struct wl_display;
@@ -4055,4 +4059,8 @@ VK_DEFINE_NONDISP_HANDLE_CASTS(anv_performance_configuration_intel, base,
 #  undef genX
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ANV_PRIVATE_H */