For compiling EasyRPG Player for your Wii you will need devkitpro.
And you will need the following libraries:
Precompiled SDL-libs can be found on the website from SDL Wii.
They can be found in the devkitpro portlibs.
Recent versions can be found here: https://github.com/carstene1ns/portlibs-wii
You need to build liblcf as portlib:
cd liblcf ./configure --host=powerpc-eabi --prefix="$DEVKITPRO/portlibs/ppc" \ --disable-shared --enable-static \ CFLAGS="-g -O2 -Wall -DGEKKO -mcpu=750 -meabi -mhard-float" make install
Once you have all dependencies above, change into the player/builds/wii folder and type 'make'. It will build a boot.dol that you can place on your sd card alongside meta.xml, icon.png and a game. That's all!
There can be some linker problems with SDL_mixer when ogg is enabled, either try to compile an ogg lib (and link against -lvorbisfile -lvorbis -lvorbisenc -logg) or recompile SDL_mixer without ogg support (remove -DOGG_MUSIC from the Makefile).
For midi you should also patch some lines in the sdl_mixer-timidity-folder (or you will have to put 20mb of "instruments" in the game root):
common.c:116: (add the lines)
config.h:173: (change the lines)
#define CONFIG_FILE "sd:/data/timidity/timidity.cfg
#define CONFIG_FILE_ETC "usb:/data/timidity/timidity.cfg