akin to what Pedro Souza and Wojciech Koszek did in the lua GSoC with
interp.h, interp_simple.c and changes to interp.c and interp_forth.c,
but completely redone from scratch.
This effectively restores the spirit of r326712 (my first attempt to
bring in Pedro's and Wojciech's work) updated for new requirements
that had silently broke their original work. This change also differs
by using fixed function names instead of function pointers to simply
things. Only one interpreter at a time may be compiled in.
Also of note: we take a mutable string, pass it in via a const char *
pointer into intrp_forth's interp_run(). We then cast away the const
to pass into ficlExec since ficl would require extensive changes to
properly const-poison. See Sections 6.5.2.5 and 6.7.3 of C11 standard
noting it's only UB if you modify a const object through a non-const
pointer, but not char [] -> const char * -> char * as here.
removing this argument, and expanding when rc is NULL. This
effectively completes the back out of custom scripts for tftp booted
loaders from r269153 that was started in r292344 with the new path
tricks that obsoleted it.
Submitted by: Netflix
Don't print when we can't find a file. Copy it instead to the error
buffer. Higher level routines determine if it's appropriate to print
the error message.
Also, remove dead code (labeled bogusly lost functionality) since we
never used that functionality. Remove unused arg from interact() too.
Sponsored by: Netflix
Create an interp class. Use it to separate out the different types of
interpreters: forth and simple with function pointers rather than
via #ifdefs.
Obtained from: lua boot loader project
(via https://bsdimp@github.com/bsdimp/freebsd.git lua-bootloader)
Sponsored by: Netflix
