Raise WARNS to 6:

Raise WARNS to 6:
- Remove NOTSET from the STYLE enumeration.  Use a new flag
  variable in main(), style_set, for this purpose.
- The ARG() macro is rather large and unwieldy, so replace it with
  an equivalent function, getarg().
- Rename a function to avoid conflict with a local variable inside
  that function.  Rename another function for consistency.
- Rename locals to avoid conflict with library function names.
- Sprinkle `const'.
- Use ssize_t instead of u_int to record line length.
- Ensure several local variables are initialized.
- Some explicit checks against NULL and 0.
- Add $DragonFly$ to Makefile.