Fix out of bounds when trying to get a pointer to empty array

multiplatform-crypto-libsodium-bindings/src/nativeMain/kotlin/com/ionspin/kotlin/crypto/util/ConversionUtil.kt

@@ -11,4 +11,10 @@ import kotlinx.cinterop.toCPointer
  * ugljesa.jovanovic@ionspin.com
  * on 27-Aug-2020
  */
-fun Pinned<UByteArray>.toPtr() : CPointer<UByteVar>? = addressOf(0)
+fun Pinned<UByteArray>.toPtr() : CPointer<UByteVar>? {
+    return try {
+        addressOf(0)
+    } catch (outOfBounds : ArrayIndexOutOfBoundsException) {
+        null
+    }
+}