Fix kotlin wallet struct access via JNA opaque pointer

build.sh

@@ -1,9 +1,13 @@
+# rust
 cargo build
 cargo test --features c-headers -- generate_headers
-cc main.c -o main -L target/debug -l bdk_ffi -l pthread -l dl -l m
-./main 
+export LD_LIBRARY_PATH=`pwd`/target/debug
+
+# cc
+cc bdk_ffi_test.c -o bdk_ffi_test -L target/debug -l bdk_ffi -l pthread -l dl -l m
+#valgrind --leak-check=full ./bdk_ffi_test
+./bdk_ffi_test
 
 # jvm
 mkdir -p jvm/build/jniLibs/x86_64_linux
 cp target/debug/libbdk_ffi.so jvm/build/jniLibs/x86_64_linux
-export LD_LIBRARY_PATH=`pwd`/target/debug