Refactor to load lua chunks compiled with 8-byte size_t elements.

src/core/org/luaj/vm2/LoadState.java

@@ -203,7 +203,7 @@ public class LoadState {
 	 * @return the {@link LuaString} value laoded.  
 	 **/
 	LuaString loadString() throws IOException {
-		int size = loadInt();
+		int size = this.luacSizeofSizeT == 8? (int) loadInt64(): loadInt();
 		if ( size == 0 )
 			return null;
 		byte[] bytes = new byte[size];

src/core/org/luaj/vm2/lib/MathLib.java

@@ -155,9 +155,8 @@ public class MathLib extends OneArgFunction {
 	}
 	static final class ldexp extends BinaryOp {
 		protected double call(double x, double y) {
-			y += 1023.5;
-			long e = (long) ((0!=(1&((int)y)))? Math.floor(y): Math.ceil(y-1));
-			return x * Double.longBitsToDouble(e << 52);
+			// This is the behavior on os-x, windows differs in rounding behavior.
+			return x * Double.longBitsToDouble((((long) y) + 1023) << 52);
 		}
 	}
 	static final class pow extends BinaryOp {