Build error under Arch Linux

[micheus]

The information is in BUILD.unix (wings3d root dir):

Setup $ERL_LIBS
===============

Create a directory to hold Erlang applications and set the
environment variable ERL_LIBS to its path.

Example:

export ERL_LIBS=/Users/bjorng/src

it's usually the place where we put the Wings3D sources under (../src/wings; ../src/cl; ../src/rebar).