I absolutely love the nature of opensource: anyone can check your code for errors and patch any bugs. After talking a little with a random developer who's interested in libhijack, he found a bug where I'm accessing a variable after calling free() on it. The fix was simple and he provided a patch for it. I'm releasing version 0.5.1 of libhijack today to fix the bug. It's a minor release. I'd recommend everyone to use this release rather than 0.5 formal.
You can find libhijack at its usual spot on SX Labs.