Quake 3 server (running under linux emulation) was failing with odd '

Quake 3 server (running under linux emulation) was failing with odd '
Protocol not available' errors.  The problem turned out to be the internal
IP_HDRINCL check that the linux emulation code in the kernel was doing in
linux_sendto().  If the internal check fails with an error, the emulation
code should simply assume that IP_HDRINCL is off rather then return the error.

The bug was introduced during the syscall separation work on this module.
FreeBSD-4.x properly ignores the error.  This patch restores behavior for
DFly.

Reported-by: Sascha Wildner <saw@online.de>