It seems from some pieces of the code like be73532 that Qt4 has been supported originally, however already v. 0.1 contains unprotected headers which do not exist in Qt4: 093bfcc

Has there been some other branch with Qt4 compatibility?

Upd. Turned out that specific header exists, but Qmake spec was wrong and failed to include required framework. But the question still stands, since the current code fails to compile with Qt4.