Build qdoc using freedesktop llvm extension
Qt need qdoc
to build qt doc.
qttools
only build qdoc
if llvm is found.
Some develop tools like qt creator may need the qt doc, and qt's cmake only find qdoc
in where qt installed rather than PATH.
So app can't use the qdoc
built in /app/qdoc
, and need to build qt manually to /app
to build qdoc
, and then build the qt doc.
Edited by catout cc