fix error on 32bit arches with size of ValvePackingSentinel_t

Index: sdk_includes/steamclientpublic.h
--- sdk_includes/steamclientpublic.h.orig
+++ sdk_includes/steamclientpublic.h
@@ -1531,7 +1531,7 @@ enum ESteamIPv6ConnectivityState
 // Define compile time assert macros to let us validate the structure sizes.
 #define VALVE_COMPILE_TIME_ASSERT( pred ) typedef char compile_time_assert_type[(pred) ? 1 : -1];
 
-#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
+#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__)
 // The 32-bit version of gcc has the alignment requirement for uint64 and double set to
 // 4 meaning that even with #pragma pack(8) these types will only be four-byte aligned.
 // The 64-bit version of gcc has the alignment requirement for these types set to
