[feature] AutotoolsToolchain: define environment when building for Android

[jcar87]

What is your suggestion?

When targetting Android and building something that requires Autotools, we need to define CC, CXX, etc, as described here: https://developer.android.com/ndk/guides/other_build_systems

if os=Android, if os.api_level and tools.android:ndk_path are defined in the profile, we have enough information to derive the correct environment variables as per the Android NDK documentation.

Currently tools.android:ndk_path is sufficient for CMakeToolchain, but not for Autotools, resulting in having to define additional variables in the profile. We could consider doing this implicitly.

See: #13373 (comment)

[SpaceIm]

We could consider doing this implicitly.

Is it really the responsibility of conan build helpers to do babysitting of cross-compilers (I mean set CC, CXX, STRIP, AR, LD, RANLIB etc, I thought it was always the responsibility of user profiles)? I'm wondering if it will not lead to crazy expectations while using conancenter recipes based on custom build systems.
It may also break android-ndk recipe depending on how it's implemented.