Fix -Werror build failure from GIT_DIFF_OPTIONS_INIT macro

[map588]

Replace compile-time GIT_DIFF_OPTIONS_INIT struct initializer with runtime git_diff_options_init() call. The macro triggers -Wmissing-field-initializers when libgit2 has more fields than the macro accounts for, which becomes a hard error under -Werror.

[map588]

@DeusData The majority of the code came from the addition of the VHDL and Devicetree grammers. This one was the source of my errors trying to build from source, and the other mitigates two potential SQL injections and a JSON argument injection to the http server.

[DeusData]

Hey @map588, I know, but for me these are seperate concerns. I would like to review the bugs in a pr, so that they can be independently reviewed and merged without the new language. New languages are a bit more complex in that regard as I need to make sure that there are no vendor risks etc. It would be nice, if you could split this PR into several ones, so that I can look into them independently. That would be awesome 🙏

[map588]

@DeusData I already did this. I closed the first PR. I should have separated them to begin with, apologies.

[DeusData]

@map588 Thanks! Will get into this as soon as I can

[jsyrjala]

I guess the same fix is also here #91

[DeusData]

Thanks! This addresses the same issue as PR #91 and issue #104. We'll review both and merge the best approach.

[DeusData]

Thanks @map588 — your fix is identical to PR #91 by @jsyrjala (same file, same line, same replacement). Since #91 was filed first, we'll merge that one. Both of you independently arrived at the correct libgit2-recommended pattern — nice work.