Build and cache libhysteria2.so (#4226)

* add submodule apernet/hysteria

* remove libhysteria2 binary from git repo

* libhysteria2.sh

* ignore *.so

libhysteria2.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+targets=(
+  "aarch64-linux-android21 arm64 arm64-v8a"
+  "armv7a-linux-androideabi21 arm armeabi-v7a"
+  "x86_64-linux-android21 amd64 x86_64"
+  "i686-linux-android21 386 x86"
+)
+
+cd "hysteria" || exit
+
+for target in "${targets[@]}"; do
+  IFS=' ' read -r ndk_target goarch abi <<< "$target"
+
+  echo "Building for ${abi} with ${ndk_target} (${goarch})"
+
+  CC="${ANDROID_NDK_HOME}/toolchains/llvm/prebuilt/linux-x86_64/bin/${ndk_target}-clang" CGO_ENABLED=1 CGO_LDFLAGS="-Wl,-z,max-page-size=16384" GOOS=android GOARCH=$goarch go build -o libs/$abi/libhysteria2.so -trimpath -ldflags "-s -w -buildid=" ./app
+
+  echo "Built libhysteria2.so for ${abi}"
+done