When decompressing with -N or -NT, strip any path from header name.

This uses the path of the compressed file combined with the name
from the header as the name of the decompressed output file.  Any
path information in the header name is stripped.  This avoids a
possible vulnerability where absolute or descending paths are put
in the gzip header.
local void cut_short(int sig)
{
    (void)sig;
    Trace(("termination by user"));
    if (g.outd != -1 && g.outf != NULL)
        unlink(g.outf);
    log_dump();
    _exit(1);
}

local void cut_short(int sig)
{
    (void)sig;
    Trace(("termination by user"));
    if (g.outd != -1 && g.outf != NULL)
        unlink(g.outf);
    log_dump();
    _exit(1);
}
