Use KDGKBMUTE and KDSKBMUTE ioctl commands conditionally

KDGKBMUTE and KDSKBMUTE do not appear in upstream linux kernel, but are
present e.g. in fedora 18 kernel headers package.
Wrap more ioctl commands in ifdefs in ioctls/vt.c

These were not available when cross-compiling to MIPS.
Take compiler name from $CC in configure.sh