android apk: build two apks. ARMv7 and ARMv8

contrib/make_apk

@@ -28,12 +28,17 @@ if [[ -n "$1"  && "$1" == "release" ]] ; then
     export P4A_RELEASE_KEYSTORE_PASSWD=$password
     export P4A_RELEASE_KEYALIAS_PASSWD=$password
     export P4A_RELEASE_KEYALIAS=electrum
+    # build two apks
+    export APP_ANDROID_ARCH=armeabi-v7a
+    make release
+    export APP_ANDROID_ARCH=arm64-v8a
     make release
 else
     export P4A_DEBUG_KEYSTORE="$CONTRIB"/android_debug.keystore
     export P4A_DEBUG_KEYSTORE_PASSWD=unsafepassword
     export P4A_DEBUG_KEYALIAS_PASSWD=unsafepassword
     export P4A_DEBUG_KEYALIAS=electrum
+    # create keystore if needed
     if [ ! -f "$P4A_DEBUG_KEYSTORE" ]; then
         keytool -genkey -v -keystore "$CONTRIB"/android_debug.keystore \
             -alias "$P4A_DEBUG_KEYALIAS" -keyalg RSA -keysize 2048 -validity 10000 \
@@ -41,6 +46,10 @@ else
             -storepass "$P4A_DEBUG_KEYSTORE_PASSWD" \
             -keypass "$P4A_DEBUG_KEYALIAS_PASSWD"
     fi
+    # build two apks
+    export APP_ANDROID_ARCH=armeabi-v7a
+    make apk
+    export APP_ANDROID_ARCH=arm64-v8a
     make apk
 fi
 

electrum/gui/kivy/tools/buildozer.spec

@@ -136,6 +136,7 @@ android.manifest.launch_mode = singleTask
 #android.wakelock = False
 
 # (str) The Android arch to build for, choices: armeabi-v7a, arm64-v8a, x86, x86_64
+# note: can be overwritten by APP_ANDROID_ARCH env var
 android.arch = armeabi-v7a
 
 # (list) Android application meta-data to set (key=value format)