add support to android jvm on termux

[tomaszduda23]

It is possible to access android classes from termux by adding new app termux-pyjnius which load python and pyjnius. pyjnius for termux is build with jnius_jvm_dlopen.pxi. It adds possibility to provide any jnienv in android. It was discussed some time ago in #247. It allows to use bellow example in termux.

from jnius import autoclass

DisplayMetrics = autoclass('android.util.DisplayMetrics')

metrics = DisplayMetrics()

WindowManager = autoclass('android.view.WindowManager')
Context = autoclass('android.content.Context')
MainActivity = autoclass('com.termux.pyjnius.MainActivity')

activity = MainActivity.mActivity
window_manager = activity.getSystemService(Context.WINDOW_SERVICE)
default_display = window_manager.getDefaultDisplay()

default_display.getMetrics(metrics)

density = metrics.density
density_dpi = metrics.densityDpi
width_pixels = metrics.widthPixels
height_pixels = metrics.heightPixels

print(f"Screen density: {density}")
print(f"Screen density DPI: {density_dpi}")
print(f"Screen width in pixels: {width_pixels}")
print(f"Screen height in pixels: {height_pixels}")