Fix configure_dev.sh so that it includes everything to build libsodium.

[derbear]

On Mac at least we need to brew install libtool, autoconf, and automake. These should be added to configure_dev.sh to simplify dev machine setup.

[iamswain25]

I was installing it on golang:latest docker, I needed to install autoconf, sudo

[jsign]

Just to mention in my env (almost vanilla Ubuntu 18.04.1) only autoconf was missing.

[algoradam]

PR #42 only fixes the mac build, we still need autoconf (and sudo?) on Linux

[jsign]

I guess this can be closed considering #189