You can obtain a full build of the SI Fixes mod on Exult's website:
https://exult.info/download.php

To build it yourself, there are 4 different methods:

1)	The Autotools way: If you have gotten the mod together with Exult's source,
	and you will be building Exult/ES too using Autotools, just add the options
	"--enable-compiler --enable-mods" to "./configure" and they will get built
	when you build Exult and installed when you install Exult. They will install
	to "$DATAROOTDIR/exult/{base-game}/mods", which may need some tweaking in
	".exult.cfg".

2)	The MinGW way: If you are using MinGW, go into the "content/bgkeyring" and
	call "make -f Makefile.mingw". Assumes you have UCC and ExPack, or have a
	way to compile them. You should edit the first few variables for the correct
	paths for tools and installation.
	
3)	Scripts: There are two scripts in "content/bgkeyring/src": "make.bat" (for
	Windows) and "make.sh" (for POSIX systems with bash); both scripts require
	UCC and ExPack. Call te appropriate one and you are done.

4)	The manual way: You will need UCC and ExPack to do it. You can do it in any
	order you want, but you have to:
	(a)	Change to the "content/sifixes/src" directory;
	(b) run "expack -i *.in";
	(c) run "ucc -o ../data/usecode usecode.uc".

To actually use the SI Fixes in Exult, you will need to use the 'sifixes.cfg'
found in the same directory as this file, as well as needing to know the path to
your Silver Seed's 'mods' directory. The 'mods' directory is by default called
'mods', and should be created in the same level as your Silver Seed's 'static'
directory.

Then, to install the SI Fixes:

  1) Copy the supplied 'sifixes.cfg' to your mods folder.
  
  2) Create the directory 'mods/sifixes' (CASE SENSITIVE -- use the exact same
     case you used in the 'sifixes.cfg' file name) and copy (or move) the
	 'sifixes/data' directory to this newly-created 'mods/sifixes' directory.
	 
That is it! Just run Exult and enjoy!
