Some refactors to main.c

[Slayer95]

I'm currently working on several features(*) I intend to PR. These refactors are meant to simplify their diffs.

(*) Features:

1. Eagerly exit / fail fast on first error found (flag +ff?)
2. Flag to disable dynamic toggling of flags from parsed code (flag +???)
3. Static build including the following APIs, supporting
   3.1. Parse in-memory buffer(s).
   3.2. Output to a buffer instead of stdout.

// Parse an in-memory buffer
int _cdecl parse_jass(char *output, const int n_max_out_size, int *n_out_size, const char* target, const int target_size);

// Parse in-memory buffers for common.j, Blizzard.j, war3map.j
int _cdecl parse_jass_triad(char *output, const int n_max_out_size, int *n_out_size, const char* buf_common, const int size_common, const char* buf_blizz, const int size_blizz, const char* buf_script, const int size_script);

// Versatile function to parse inputs as if they were passed to latest ``pjass`` binary. (``doparse`` can be refactored to use it.)
int _cdecl parse_jass_custom_r(char *output, const int n_max_out_size, int *n_out_size, const int targets_or_opts_count, const char **targets_or_opts);

// Versatile function to parse inputs with fine-grained control over each file/buffer's flags. (This is my main use case.)
int _cdecl parse_jass_custom(char *output, const int n_max_out_size, int *n_out_size, const int targets_count, const int *targets_sizes, const char **targets, const char **flags);

Do let me know if you find some of these features/APIs useless or w.e.