qnetworkinterface_unix.cpp getifaddrs path declares `struct ifreq ifr` to pass
to getMtu(), but Redox relibc <net/if.h> provides only interface flags and the
if_nameindex() helpers -- no struct ifreq (Redox has no SIOCGIF* ioctls). The
SIOCGIFMTU body in getMtu() is #ifdef-guarded and compiles out, so the type
only needs to be complete. Define a minimal-but-standard struct ifreq under
#if defined(__redox__) at file scope; the ioctls that would use it fail
gracefully at runtime (mtu stays 0). Durable patch, wired into qtbase recipe.
vasilito
41bc2a63e2