D compiler for Android

[Joakim via digitalmars-d-ldc]

Heh, just built a test runner apk in the Termux app on Android, 
without using the Android NDK at all and building and signing the 
apk using OpenSSL, ie without using the SDK either, since they 
don't provide an Android NDK or SDK that runs natively on 
Android. :)

The new test runner apk passes all the same tests as before, plus 
it's down to a handful of disabled tests across only four modules 
now, down from six modules before: three unit test blocks across 
two modules in druntime (really just one unit test block in 
core.thread, because the other two from rt.lifetime pass but 
cannot be run before some other tests in the same test run), a 
couple test cases in std.datetime which leak memory because of a 
custom test-only range, and two asserts and one static assert in 
std.math, all related to testing hypot.

Of course, a handful of workarounds and lower optimization flags 
were used to get here, which will have to be cleaned up going 
forward.  I'll polish those up over time.

Time to start writing up some PRs and put out some new test 
builds, including one for Android/ARM and hopefully an official 
Termux package.