refactor: allow specifying target arch in Android build script (#383)

Fixes #375

scripts/build-android.sh

@@ -3,33 +3,45 @@
 # Setup
 BUILD_DIR=platform-build
 mkdir $BUILD_DIR
-cd $BUILD_DIR
+cd $BUILD_DIR || exit
 
 # Create the jniLibs build directory
 JNI_DIR=jniLibs
 mkdir -p $JNI_DIR
 
 # Set up cargo-ndk
-cargo install cargo-ndk
+cargo install cargo-ndk --locked
+
+# Add targets
 rustup target add \
-        aarch64-linux-android \
-        armv7-linux-androideabi \
-        x86_64-linux-android \
-        i686-linux-android
+  aarch64-linux-android \
+  armv7-linux-androideabi \
+  x86_64-linux-android \
+  i686-linux-android
 
 # Build the android libraries in the jniLibs directory
-cargo ndk -o $JNI_DIR \
-        --manifest-path ../Cargo.toml \
-        -t armeabi-v7a \
-        -t arm64-v8a \
-        -t x86 \
-        -t x86_64 \
-        build --release 
-
-# Archive the dynamic libs
-cd $JNI_DIR
-tar -czvf ../EmbeddedMilliAndroid.tar.gz *
-cd -
-
-# Cleanup
-rm -rf $JNI_DIR
+if [ "$#" -eq 0 ]; then
+  cargo ndk -o $JNI_DIR \
+    --manifest-path ../Cargo.toml \
+    -t armeabi-v7a \
+    -t arm64-v8a \
+    -t x86 \
+    -t x86_64 \
+    build --release
+  # Archive the dynamic libs
+  cd $JNI_DIR || exit
+  tar -czvf ../EmbeddedMilliAndroid.tar.gz ./*
+  cd - || exit
+  # Cleanup
+  rm -rf $JNI_DIR
+elif [ "$1" = "x86" ]; then
+  cargo ndk -o $JNI_DIR --manifest-path ../Cargo.toml -t x86 build --release
+elif [ "$1" = "x64" ]; then
+  cargo ndk -o $JNI_DIR --manifest-path ../Cargo.toml -t x86_64 build --release
+elif [ "$1" = "armv7" ]; then
+  cargo ndk -o $JNI_DIR --manifest-path ../Cargo.toml -t armeabi-v7a build --release
+elif [ "$1" = "arm64" ]; then
+  cargo ndk -o $JNI_DIR --manifest-path ../Cargo.toml -t arm64-v8a build --release
+else
+  echo "Invalid architecture: '$1'"
+fi