Bzip2

Bzip2
Bzip2 is a high-quality, patent free file compressor using the Burrows-Wheeler algorithm. Files are typically compressed to anywhere between 10% - 15% of their original size while maintaining a speed of roughly twice the speed of compression and up to six times the speed of decompression of the PPM compression family. Any machine with an ANSI C compiler should be able to support bzip2, making it a great choice for those who run systems with portable demands.

Emerge
After adjusting USE flags: