The linker situation is a mess.  Basically, the mkDIR.pl script
and the DIR file that it creates need debugging.

vm.c really needs to be loaded first.

_CCARGC unresolved (not including call.asm).

Assembler inline in parse() in csyslib.c needs rework.
Assembler inline in __bdos2 in csyslib.c needs rework.
Assembler inline in __hitkey in csyslib.c needs rework.
Assembler inline in __getkey in csyslib.c needs rework.
Assembler inline in __strlen in strlen.c needs rework.
Assembler inline in __iscons in iscons.c needs rework.
Assembler inline in _abort in exit.c needs rework.
Assembler inline in _isatty in isatty.c needs rework.

Uncommented lowercase "public" for _fputc (inline assembler?).

Files with #asm directives:
  csyslib.c exit.c fgetc.c fputc.c
  free.c isatty.c iscons.c rename.c
  strlen.c unlink.c

Anything still marked BUGBUG: in the code:
;BUGBUG __asl, __asr are missing!
; BUGBUG: __div is missing!
; BUGBUG: __imul is missing!
; BUGBUG: __mod is missing!