LK8000 is an OpenSource project, distributed under the GNU GPL license.
You can modify the source code to meet your requirements, and eventually you can submit your changes so that they can be incorporated in the official version, for the benefit of all users.
Source code is available on the social coding hub at https://github.com/LK8000/LK8000
LK8000 is written in C and C++ under Linux, and cross-compiled for Windows CE and Windows 32 platform using the Mingw tools and derivates.
Particularly, Mingw32ce is used for the Arm platforms. The package you download is in a tar.gz format (taz), and to compile it you normally do a "make clean; make TARGET=PC" or, in place of PC, PNA PPC2002 PPC2003 etc.
Of course you can create your own tools for compiling. Please do not submit suggestions on the makefile because every user has his own preference. If you want to contribute, there are far more important things to look at, than to change tools.