When I tried this, it didn’t seem to install the libSDL .h files … maybe I missed something, I’ll try again.
EDIT I got it working 
… using “pkgman” seems to have helped, as you mention, to install the two dependencies - thank you! That helped. Then as per the Gnukem readme instructions on github I did:
~> git clone GitHub - davidjoffe/dave_gnukem: Dave Gnukem is a cross-platform 2D scrolling platform shooter inspired by Duke Nukem 1
~> cd dave_gnukem
~/dave_gnukem> git clone GitHub - davidjoffe/gnukem_data: Game data subfolder for https://github.com/davidjoffe/dave_gnukem (important) data
~/dave_gnukem> make
~/dave_gnukem> ./davegnukem
Sound works too.
I had to make one change to the Dave Gnukem Makefile - the “INCLUDEDIRS=” line should read:
INCLUDEDIRS=sdl-config --cflags
(Edit4 I’ve now committed a small update to the official Makefile that should detect Haiku automatically)
EDIT2 Of course now a more difficult part would be making a package (Someone mentioned this game had a BeOS port. It did as I recall in the past, but I was not involved with that at all … doesn’t matter anymore.)