JFFS2 ZLIB compression support

configname: CONFIG_JFFS2_ZLIB

Linux Kernel Configuration
└─>File systems
└─>Miscellaneous filesystems
└─>JFFS2 ZLIB compression support
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Zlib is designed to be a free, general-purpose, legally unencumbered,
lossless data-compression library for use on virtually any computer
hardware and operating system. See <http://www.gzip.org/zlib/> for
further information.

Say 'Y' if unsure.