A quick look on bcrypt's webpage tells me this is not a library, but a program. If you want to have it as a library, there is not support for this out of the box. You need to figure it out by yourself.
The general instructions for building are to use make. (Usually, nmake is the equivalent on Windows.) I don't see any instructions for Windows on the webpage. You'll have to look through the README's, etc. to figure it out. cmake and qmake will not help as these will just generate makefiles and not compile anything. However, there is already a makefile, so you don't have to run cmake or qmake to create them.
