Building fails on Freebsd12

[wakwanza]

MongooseIM version: 4.1.0
Installed from: source (release tarball)
Erlang/OTP version: 23.2.4 (kerl install)

Describe the issue.
Building from source fails at the following point:

`===> Compiling cowboy
===> Compiling lasse
===> Compiling p1_utils
_build/default/lib/p1_utils/src/p1_server.erl:1005: Warning: sys:get_debug/3 is deprecated; incorrectly documented and only for internal use. Can often be replaced with sys:get_log/1

_build/default/lib/p1_utils/src/p1_fsm.erl:831: Warning: sys:get_debug/3 is deprecated; incorrectly documented and only for internal use. Can often be replaced with sys:get_log/1

===> Compiling mysql
===> Compiling stringprep
===> Compiling c_src/stringprep.cpp
===> Linking /opt/MongooseIM-4.1.0/_build/default/lib/stringprep/priv/lib/stringprep.so
===> Compiling eodbc
===> Compiling c_src/odbcserver.c
===> Linking /opt/MongooseIM-4.1.0/_build/default/lib/eodbc/priv/eodbcserver
gmake: *** [Makefile:31: rel] Error 1`