Fixes weird link errors of the form:

      CCLD     Xvfb
    ../../Xext/.libs/libXext.a(xvmc.o): In function `xf86XvMCRegisterDRInfo':
    /home/ajax/git/xserver/Xext/xvmc.c:828: undefined reference to `strlcpy'
    /home/ajax/git/xserver/Xext/xvmc.c:829: undefined reference to `strlcpy'
    ../../os/os.O: In function `siHostnameAddrMatch':
    /home/ajax/git/xserver/os/access.c:1821: undefined reference to `strlcpy'
    ../../os/os.O: In function `AuthAudit':
    /home/ajax/git/xserver/os/connection.c:555: undefined reference to `strlcpy'
    /home/ajax/git/xserver/os/connection.c:574: undefined reference to `strlcpy'
    ../../os/os.O:/home/ajax/git/xserver/os/log.c:972: more undefined references to `strlcpy' follow
    collect2: error: ld returned 1 exit status
    Makefile:688: recipe for target 'Xvfb' failed
    make[3]: *** [Xvfb] Error 1
    Makefile:749: recipe for target 'all-recursive' failed
    make[2]: *** [all-recursive] Error 1
    Makefile:608: recipe for target 'all-recursive' failed
    make[1]: *** [all-recursive] Error 1
    Makefile:776: recipe for target 'all-recursive' failed
    make: *** [all-recursive] Error 1

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>