2.4.2: "make check" fails without json & lpeg Lua modules

Hi,

Basically $SUBJECT. If you run "make check" after a successful build, it will fail unless you have the Lua modules "json" and "lpeg" installed.

Not a huge problem, I got them from https://github.com/harningt/luajson and https://www.inf.puc-rio.br/~roberto/lpeg/, but as this sees to be a new thing with 2.4.2 I thought I'd give you a heads-up.

HAND Thomas