Depends (indirectly) on Erlang development environnement

[bortzmeyer]

==> earmark_parser
Compiling 1 file (.yrl)
/usr/lib/erlang/lib/parsetools-2.3.1/include/yeccpre.hrl: no such file or directory
could not compile dependency :earmark_parser, "mix compile" failed. You can recompile this dependency with "mix deps.compile earmark_parser", update it with "mix deps.update earmark_parser" or clean it with "mix deps.clean earmark_parser"

This is because the file yeccpre.hrl is distributed only with Erlang development files. An Erlang runtime is not enough. IMHO, it is worth to mention this dependency (on Debian, just install the package erlang-dev).

[josevalim]

Can you please send a pull request that updates the README? :)

[bortzmeyer]

Can you please send a pull request that updates the README? :)

Done, see #1442.