[meson] Add needed compiler flags

[ebraminio]

Are based on https://github.com/harfbuzz/harfbuzz/blob/2.6.4/configure.ac#L86

@tp-m Can you help on the comments on the patch and review please?

@khaledhosny @behdad just have merged meson port https://github.com/harfbuzz/harfbuzz/pull/1437/files and applied 1c3f80b c494d7a on top, let's reach to some acceptable level at least to remove CMake port before the release, please have a look at the changes and give me and @tp-m your feedbacks, thanks!

[tp-m]

Why not use this for mingw?

Ideally you'd just check if the compiler supports it as above without special-casing.

If special-casing is needed then perhaps if cpp.get_id() = 'gcc' and host_machine.system() == 'windows'

[ebraminio]

Why not use this for mingw?

560d68a and e3320ec

as Windows are by default are trying to hide the symbols by default I guess

[tp-m]

IIRC mingw by default exports all symbols (in general, don't know about inline functions, I would expect those not to be exported), msvc by default exports no symbols.

Personally, I would use the meson port as an opportunity to start over and ignore cruft like that, and only fix it if it still causes issues.

I don't fully understand these commits, probably missing context (didn't look what that script does).

[ebraminio]

Personally, I would use the meson port as an opportunity to start over and ignore cruft like that, and only fix it if it still causes issues.

Ok, let's comment it, what do you think about those ARM ones? Comment those as well?

[tp-m]

Also, we need to check for != 'windows' here if we want to do if it not mingw. My bad, sorry.

And you don't need the braces in if (foo and bar) for what it's worth.

[tp-m]

Actually:

if host_machine.cpu_family() == 'arm' and cpp.alignment('struct { char c; }') != 1
  add_global_arguments(cpp.get_supported_arguments(['-mstructure-size-boundary=8']), language : 'cpp')
endif

or

if host_machine.cpu_family() == 'arm' and cpp.alignment('struct { char c; }') != 1
  if cpp.has_argument('-mstructure-size-boundary=8')
    add_global_arguments('-mstructure-size-boundary=8', language : 'cpp')
  endif
endif

And one more thing: we shouldn't use add_global_arguments() but add_project_arguments() - the difference matters if harfbuzz is used as a meson subproject. We only want these things to apply to harfbuzz.

[ebraminio]

Oh. At this point the patch has come more of your work than mine, can I close this so you upload it again? :)

[tp-m]

Nah, don't worry about it. I don't need any credit for that, have enough in the history of the meson port. Thanks for handling this instead of just leaving it to me! (unless you'd rather I JFDI of course - which I can do but only later.)

[ebraminio]

Oh, so have a look :)

[tp-m]

lgtm