Update build script

Author: colemancda

Demo/build-swift.sh

@@ -3,6 +3,7 @@ set -e
 source swift-define
 
 # Build with SwiftPM
+export JAVA_HOME=$SWIFT_ANDROID_SYSROOT/usr
 xcrun --toolchain swift swift build -c $SWIFT_COMPILATION_MODE \
     --swift-sdk $SWIFT_TARGET_NAME \
     --toolchain $XCTOOLCHAIN \