Log Message:
update to 1.2.3
this fixes (at least) another security problem (DoS, CAN-2005-1849)
changes:
-Eliminate a potential security vulnerability when decoding invalid
 compressed data
-Eliminate a potential security vulnerability when decoding specially
 crafted compressed data
-Fix a bug when decompressing dynamic blocks with no distance codes
-Fix crc check bug in gzread() after gzungetc()
-Do not return an error when using gzread() on an empty file