Add support for querying timezone on Android

[skyline75489]

No description provided.

[skyline75489]

OK the code does not work. The compiler complains:

error[E0283]: type annotations needed
   --> src/output/table.rs:324:20
    |
324 |             return CompiledData::parse(output.stdout);
    |                    ^^^^^^^^^^^^^^^^^^^ cannot infer type
    |
    = note: cannot satisfy `_: CompiledData`
    = note: required by `zoneinfo_compiled::CompiledData::parse`

error: aborting due to previous error; 1 warning emitted

But I honestly don't know what's wrong with it.

[ariasuni]

CompiledData is a trait, and TimeZone is implementing this trait:

Suggested change

	return CompiledData::parse(output.stdout);
	return TimeZone::parse(output.stdout);

[ariasuni]

I suppose it’s a good practice to include the “documentation” for this change.

Suggested change

	if env::consts::OS == "android" {
	// https://android.googlesource.com/platform/bionic/+/master/libc/tzcode/bionic.cpp
	if env::consts::OS == "android" {

[ariasuni]

Well actually your approach is wrong. persist.sys.timezone doesn’t contain the data to parse but I guess the filename relative to the directory containing the TZDATA, and Bionic’s source code seems to also take into account the «first format» described at https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html.

I’m really starting to think we should stop trying to replace the libc and use standard C function so that compatibility with OS isn’t such a nightmare of trying to understand what such or such libc are actually doing.

[skyline75489]

Closed in favor of #867