QT5_ADD_RESOURCES with generated .qrc triggers "ninja: warning: multiple rules generate..."
When passing a .qrc file to QT5_ADD_RESOURCES which is generated using add_custom_command, ninja will complain about there being multiple rules to generate the .qrc file.
To reproduce: (from directory containing files: CMakeLists.txt test.qrc.in)
mkdir build && cd build cmake .. -G Ninja ninja cmake . ninja
Note that only the second ninja call will generate the warning. Also in this reduced example everything still seems to work fine in spite of the warning, but in our real build system where we encountered this issue ninja would sometimes get into an infinite loop and abort the build completely.
(cmake 3.7.2, ninja 1.7.2)