libvncserver: bump version to 0.9.10

[Thomas:
 - add comment about AUTORECONF = YES, noticed by Baruch Siach, and
   suggested by Yann E. Morin.
 - add dependency on host-pkgconf, since the configure script uses
   PKG_CHECK_MODULES.]

Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>