lynx-dev problems with dev16 on DOS

[Vlad Harchev]

  LYEditmap.c can't be compiled if EXP_ALT_BINDINGS is not defined. I assume
it's defined by configure automatically (I may be wrong), but the fact is - 
lynx can't be compiled on DOS if EXP_ALT_BINDINGS is not defined. Defining it
in LYEditmap.c solves the problem :)

 Seems this should be fixed, otherwise all makefiles for DOS supplied
with lynx will fail compiling that file.

 Best regards,
  -Vlad