Disallow relative paths in Findlib configuration (#3161)
Disallow relative paths in Findlib configuration (#3161)

We treat such paths incorrectly. Better report an error instead.

Signed-off-by: Andrey Mokhov <251bbb147316c69f1038239e09718efe08bbf2d1@janestreet.com>
dra27/jbuilder,dra27/jbuilder,dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder