Add a (build-flag controlled) option to have the produced binary app support julia flags

[NHDaly]

Sometimes, for debugging, we'd like to enable a julia flag in our statically compiled binary. (In this case, it was --check-bounds=yes.)

But in order to enable it at runtime, in the binary, we would need to edit the embedding_wrapper.c file, here:

PackageCompiler.jl/src/embedding_wrapper.c

Lines 52 to 53 in 7cab589

	jl_options.image_file = JULIAC_PROGRAM_LIBNAME;
	julia_init(JL_IMAGE_JULIA_HOME);

It would be awesome if we instead add a build-time controlled flag, similar to what we did in #551, which would statically enable a feature in the embedding_wrapper.c file to call julia's jl_parse_opts() with arguments passed at the command line? Maybe collecting all the args that start after --jl_args or something like that?

This could look something like this, maybe?:

#ifdef JL_PARSE_JL_ARGS
// find the start of `--jl_args`, if it's present, in `argv`:
int jl_args_start = find_jl_args_start(argc, argv);

int new_argc = argc - jl_args_start;
char **new_argv = argv + jl_args_start;
jl_parse_opts(&new_argc, (char***)&new_argv);

argc = jl_args_start-1;

#endif

and then the julia flag would control the JL_PARSE_JL_ARGS macro being defined.

Would you be open to that? Or something similar? Thanks @KristofferC.

[KristofferC]

I don't understand what the difference between this and #565 is.

[NHDaly]

<3 there is no difference. My mistake - i tried searching the issue list, but i couldn't find anything! Apologies for the duplicate.

[NHDaly]

I guess the only difference is that we might want to support disabling this at build time, so that users who don't want to expose arbitrary julia flags can have the option to turn this flag off? But yeah, thanks i think this is sorted.