Building Pokeemerald's PC Port (Lubuntu 16.04.6 LTS)

1) Open your terminal and make sure that you have the latest version of the package lists for your Linux distro by using sudo apt update

2) Let's install most of the tools and libraries required to build the Pret decompilation projects:
sudo apt install build-essential git make i686-w64-mingw32-gcc g++-mingw-w64-i686

3) Let's clone the PC Port's source code.
git clone https://github.com/sierraffinity/pokeemerald -b pc-port pokeemerald_pc

For reference, I cloned it inside a folder called "Decomps" that I have in my home folder (/home/lunos).

4) Now we'll put that aside for a while to download devkitpro-pacman's .deb installer from here:
https://github.com/devkitPro/pacman/releases

Double click it and install it normally.

5) Go back to the terminal and update the package list of dkp-pacman by using sudo dkp-pacman -Sy on your terminal.

6) Install the gba-dev tools by using sudo dkp-pacman -S gba-dev

7) Download SDL from https://www.libsdl.org/download-2.0.php
You need the Development Libraries for MinGW specifically, and the Runtime Library for 32-bit Windows as well.

8) Uncompress the Development Libraries (SDL2-devel-2.0.12-mingw.tar.gz) twice. Then drag and drop the SDL2-2.0.12 folder in /home/lunos/Decomps/pokeemerald_pc/tools to keep things clean.

9) Uncompress the Runtime Libraries (SDL2-2.0.12-win32-x86.zip) once, and drag-and-drop the SDL2.dll file in /home/lunos/Decomps/pokeemerald_pc.

10) Modify the path to SDL in pokeemerald_pc's Makefile_pc like so:
SDL_DIR := /home/lunos/Decomps/pokeemerald_pc/tools/SDL2-2.0.12/i686-w64-mingw32

11) Back to the terminal
cd pokeemerald_pc
make tools
make -f Makefile_pc -jN
Note: "N" stands for the number of CPU Threads you want to assign to the compiler. The more threads, the faster it'll go.

12) Wait until it's done. Once it is, you should find pokeemerald.exe in /home/lunos/Decomps/pokeemerald_pc, so open it through Wine and have fun.