Optimize ch.protonvpn.android build recipe

metadata/ch.protonvpn.android.yml

@@ -1186,7 +1186,8 @@ Builds:
         libldap2-dev gperf bison bzip2 flex swig
     gradle:
       - prod
-    output: build/outputs/apk/prod/release/ProtonVPN-*-prod-release-unsigned.apk
+    srclibs:
+      - android-ndk-boringssl@ndk-static
     rm:
       - app/src/main/jniLibs/x86/*
       - app/src/main/jniLibs/x86_64/*
@@ -1200,8 +1201,7 @@ Builds:
       - sed -i -e '/triple/d' -e '/play\ {/,+4d' build.gradle
       - git submodule update --init --recursive ../strongswan
       - cd ../strongswan
-      - git clone git://git.strongswan.org/android-ndk-boringssl.git -b ndk-static
-        src/frontends/android/app/src/main/jni/openssl
+      - ln -s -T $$android-ndk-boringssl$$ src/frontends/android/app/src/main/jni/openssl
       - cd ..
       - echo ndk.dir="$(pwd)"/ndk/android-ndk-r21e > strongswan/src/frontends/android/local.properties
     scandelete:

srclibs/android-ndk-boringssl.yml

@@ -0,0 +1,2 @@
+RepoType: git
+Repo: git://git.strongswan.org/android-ndk-boringssl.git