SafeSocketNotifier: fix socket FD type
Qt uses qintptr for the socket file descriptor and has a new overload for the activated() signal in 5.15. This fixes a compile error when building for the x86_64-w64-mingw32 architecture.
Qt uses qintptr for the socket file descriptor and has a new overload for the activated() signal in 5.15. This fixes a compile error when building for the x86_64-w64-mingw32 architecture.