Enable read environment variable on Android

[RenfengLiu]

This fixs: #430

[CLAassistant]

All committers have signed the CLA.

[rpavlik]

The underlying issue is that there's no way to set those environment variables from outside the app, so they don't actually serve the purpose intended. (though, there may not be implicit layer support on android at all yet? or maybe just from manifests?)

A port of the behavior is more likely to be using getprop with some prefix before the environment variable name, I suspect.

What's your use case?

[RenfengLiu]

There are two ways applications can set the environment variable:

• The wrap properties: https://source.android.com/docs/security/test/asan#using_the_wrap_property
• And the wrap script: https://developer.android.com/ndk/guides/wrap-script

[RenfengLiu]

The underlying issue is that there's no way to set those environment variables from outside the app, so they don't actually serve the purpose intended. (though, there may not be implicit layer support on android at all yet? or maybe just from manifests?)

A port of the behavior is more likely to be using getprop with some prefix before the environment variable name, I suspect.

What's your use case?

The use case is hoping that there's will same mechanism used in other platforms that can load the explicit layer or implicit layer when requested. The implict layers without the enable_environment works, but this loads the layer for all applications, which is not the desired behavior.

Using getprop would be another option, but this might require the Android system reserve that prop.

[rpavlik-bot]

An issue (number 2160) has been filed to correspond to this pull request in the internal Khronos GitLab (Khronos members only: KHR:openxr/openxr#2160 ), to facilitate working group processes.

This GitHub pull request will continue to be the main site of discussion.