This is an edge case of how the lexer changes behavior when
reading string literals versus reading unquoted source code.
Three double quotes would begin a multi-line string literal,
but just two are still ambiguous, so it has to `peek()` to
see whether it's inside a multi-line string literal or
outside an empty regular string.
* Implement warning diagnostic flags for RGBFIX
* `-m/--mbc-type help` prints to stdout
* Support `-m list` as well as `-m help`
* Make invalid `rgbfix -l` characters a fatal error, like other invalid CLI arguments
* Refactor fix/main.cpp into multiple files
- Single unified routine for erroring out or handling missing dependencies
- Single three-state enum instead of two Booleans for missing dependencies
(this causes `-MC` to imply `-MG` instead of needing `-MG -MC`)
- Functions than can miss included files return a Boolean for whether the
parser should `YYACCEPT` and exit
* No need to use `locale`s
* Implement octal numbers, `_` digit separators, and `0x/0b/0o` prefixes in linkerscripts
* Refactor some functions out of `yylex`
* Support `\0` in linkerscripts
This feature is referred to as "code/data literals" in ASMotor,
and simply as "literals" in some older assemblers like MIDAS
for the PDP-10. RGBASM already had the "section fragments"
feature for keeping disparate contents together when linked,
so these worked naturally as "fragment literals".
* Remove `err` and `warn`, keep `errx` and `warnx`, using them in RGBGFX too
* Separate RGBGFX and RGBLINK warnings/errors from main options
* Separate `report` function into `error` and `fatal` messages
* Implicit newlines for most RGBASM errors
