Running "LOCALBASE=/boot/common/ python setup.py" tells the config where to find libpng and libjpeg. (This invokes a whole new list of "more then 10 operands in asm" though, but can be compiled with the adding && !defined(__HAIKU__) on the lines concerned)

Libscrap  http://code.google.com/p/libscrap/source/checkout can be compiled also on Haiku, you just need to rename the line:

Dependency('SCRAP', , 'libX11', X11?),

into

Dependency('SCRAP', , 'libscrap', scrap?),

in config_unix.py

Running tests seems to be ok, some I can't check here (no sound on this laptop in Haiku)

Checked against a small game:  http://bfruit.sourceforge.net/