Update Android min NDK version to 23.x?

[Michael Weghorn]

On 25/01/2023 14.14, Michael Weghorn wrote:
> For the Android build, configure.ac currently checks for a minimum NDK 
> version of 16.x and the Jenkins builds use 20.1.5948944 (s. 
> distro-configs/Jenkins/android_common.conf ).
> 
> In the context of adding support for newer NDKs, I would like to update 
> the minimum version to 23.x to avoid the complexity that would be needed 
> to support older versions in parallel.
> 
> Updating to NDK 23 would among others allow using lld for linking 
> liblo-native-code.so, which significantly reduces the time for linking 
> in debug builds (~40s -> ~10s for me for an x86 build) and also fixes an 
> error I get for 64-bit-ARM debug builds (for which I had a local 
> workaround so far, s. https://gerrit.libreoffice.org/c/core/+/130947 ).
> 
> AFAICT, this should have no impact on runtime requirements/supported 
> devices, since NDK 23 still supports API 16 (Android 4.1).
> 
> 
> Suggested changes in Gerrit:
> https://gerrit.libreoffice.org/c/core/+/146118
> https://gerrit.libreoffice.org/c/core/+/146119
> 
> (Changes further up the relation chain are for supporting NDK 24 and 25 
> as well.)
> 
> In addition to the above changes, installing the corresponding NDK for 
> all Android builders is needed, don't know about additional custom 
> config for android builders beyond above-mentioned 
> distro-configs/Jenkins/android_common.conf )

As discussed in the ESC call on 2023-01-26 [1], Jenkins builders have 
been switched to NDK 25 now (thanks, Cloph!) and I have merged the 
pending Gerrit changes and updated the documentation on Android baseline 
in README.md.


[1] 
https://lists.freedesktop.org/archives/libreoffice/2023-January/089878.html