id_sd is next; Music and digitized sound support is technically disabled, but do-nothing functions are still in there (just in case, for now). Should also import a bit of code from the Cat3D work.
Little bits of id_us ASM porting, including id_us_a.asm
More ASM updates, again using Cat3D (CGA graphics only)
Actually add ASM files ports (again CGA only)
Imported untested SDL backend from Cat3D partial porting attempt
Converted external resources to (more) portable C code
Imported DOSBox OPL emulator (Cat3D), added Makefile, misc. fixes
Don't access TimeCount directly
Codebase compiles and links, but is far from ready and tested (just for one example, some structs should be packed)