When building a Qt project, the AUTORCC functionality, by default,
uses the rcc binary to get the contents of a qrc file for
dependency information. This is done at CMake "generate" time.

The problem is that while configuring Qt itself, the rcc binary is
not built yet.
In that case, to get the contents of the qrc file, fall back to
the code branch which uses an ifstream instead of the rcc binary.