From the INSTALL file:
GHOSTSCRIPT BUGS
----------------
* Well Tempered Screening (WTS) works with ghostscript 8.54 thru 8.62+.
So if you want BEST COLORS, you'll have to install gs 8.54 or better
if you don't have it.
$ gs --version
8.15.2
$ wget "http://mirror.cs.wisc.edu/pub/mirrors/ghost/GPL/gs862/ghostscript-8.62.tar.gz"
$ tar zxf ghostscript-8.62.tar.gz
$ cd ghostscript-8.62
$ ./autogen.sh
$ make
$ su OR $ sudo cp bin/gs /usr/bin/gs.foo
# cp bin/gs /usr/bin/gs.foo
(Optional)
# make install OR $ sudo make install
$ gs.foo --version
8.62
* Ghostscript before 8.55 has a problem with ICM files and 64-bit gcc.
It causes a segfault with km2430_2.icm. So don't select that one.