I've just built the Qt libraries (on Windows) from source and it seems that the build-path is actually built into the library binaries themselves! This makes moving the binaries to another machine or directory difficult (but not impossible - see Change Qt install path after building?)
I've never come across this in any other library I've used and was wondering why it is the way it is? Is this just a remnant of a solution some obscure unix "install" issue, or is there a good reason for it?