The previous implementation used strtol() for parsing hex literals, which only supports up to 32-bit values on 32-bit architectures. This caused hex literals larger than 0x7FFFFFFF to overflow or fail. Changed to strtoll() which guarantees 64-bit parsing regardless of platform word size.
Also updated the error message to include the actual sizeof(long int) for debugging, uncommented the previously disabled 64-bit hex literal examples in syntax.wren, and added a test case for 0xdeadbeef to verify the fix works correctly.