Compile:
A "make" should be enough, "make install" copies the binary to
$(GIMP_DIR)/plug-ins.

This plug-in requires GNU flex and bison. I haven't tested, if normal lex
and yacc work.
I've got these versions of flex and bison installed:
bison: 1.25
flex: 2.5.4

Flex is required to link against libfl.

Install:
Put this into your ~/.gimp/gimprc file:
(userfilter-path "${gimp_dir}/userfilter:${gimp_data_dir}/userfilter")

I added a library of Freeware filters by Andrew Buckle, it's the
file "AndrewsFilters.ffl" in the "userfilter" directory. Move this
file to either "~/.gimp/userfilter" or the global
${gimp_data_dir]/userfilter.