ci: Add build check CI for Android platform
This MR pulls in a bunch of Android headers and adds an android_stub, such that we can compile check EGL and the Vulkan drivers on the Android platform. There's a bunch of fixes for problems that that uncovers and then finally a new CI target - meson-android.
@anholt @daenzer for CI @dbaker for meson @jekstrand @llandwerlin for anv
Edited by Kristian H. Kristensen