cl.exe and clang-cl have no ssize_t

[makotokato]

When integrating ICU4X with Firefox, Window build cannot compile icu_capi (try build log is https://treeherder.mozilla.org/logviewer?job_id=413380887&repo=try&lineNumber=19287)

[task 2023-04-22T08:23:15.509Z] 08:23:15    ERROR -  /builds/worker/checkouts/gecko/third_party/rust/icu_capi/c/include/diplomat_runtime.h(57,24): error: unknown type name 'ssize_t'
[task 2023-04-22T08:23:15.509Z] 08:23:15     INFO -  MAKE_SLICE_VIEW(Isize, ssize_t)

When looking diplomat code, runtime.h uses ssize_t. But cl.exe (and clang-cl.exe) doesn't have ssize_t. Could you use ifdef or something workaround?

If I am something wrong, let me know.

[Manishearth]

Do we know what types we should use here?

[Manishearth]

It also seems like it's standard and has existed for a while so it might just need some flags

[Manishearth]

Ah, it's POSIX standard, not C standard.

[Manishearth]

Apparently it should be intptr_t or ptrdiff_t

[makotokato]

I think that intptr_t is better, but both is OK.

[sffc]

I've always seen just size_t

[Manishearth]

For isize? Seems like a potential hazard and a potential ABI mismatch

[sffc]

oh I didn't see this was for signed.

[Manishearth]

#327

@makotokato do you need an icu_capi patch release with these changes?

[Manishearth]

icu_capi patch in unicode-org/icu4x#3401