[REG 3.1.2 -> 3.3.1] Malformed project file crashes Creator

1   __GI_raise                                  raise.c            54   0x7ffff555b418 
2   __GI_abort                                  abort.c            89   0x7ffff555d01a 
3   qt_message_fatal                            qlogging.cpp       1680 0x7ffff617aec0 
4   QMessageLogger::fatal                       qlogging.cpp       793  0x7ffff6176dc4 
5   qt_assert                                   qglobal.cpp        3063 0x7ffff616f5dd 
6   QMakeInternal::IoUtils::fileType            ioutils.cpp        45   0x7fffe38a0bb6 
7   QMakeInternal::IoUtils::exists              ioutils.h          47   0x7fffe38758d7 
8   QMakeEvaluator::evaluateBuiltinConditional  qmakebuiltins.cpp  1647 0x7fffe388eb11 
9   QMakeEvaluator::evaluateConditionalFunction qmakeevaluator.cpp 1737 0x7fffe38730f2 
10  QMakeEvaluator::visitProBlock               qmakeevaluator.cpp 649  0x7fffe386ae8c 
11  QMakeEvaluator::visitProBlock               qmakeevaluator.cpp 561  0x7fffe386a72f 
12  QMakeEvaluator::visitProBlock               qmakeevaluator.cpp 561  0x7fffe386a72f 
13  QMakeEvaluator::visitProLoop                qmakeevaluator.cpp 810  0x7fffe386ba03 
14  QMakeEvaluator::visitProBlock               qmakeevaluator.cpp 582  0x7fffe386a92b 
15  QMakeEvaluator::visitProBlock               qmakeevaluator.cpp 513  0x7fffe386a41d 
16  QMakeEvaluator::visitProFile                qmakeevaluator.cpp 1432 0x7fffe387046c 
17  QMakeEvaluator::evaluateFile                qmakeevaluator.cpp 1904 0x7fffe3873e59 
18  QMakeEvaluator::evaluateFeatureFile         qmakeevaluator.cpp 2006 0x7fffe387487f 
19  QMakeEvaluator::evaluateConfigFeatures      qmakeevaluator.cpp 1320 0x7fffe386fbd7 
20  QMakeEvaluator::visitProFile                qmakeevaluator.cpp 1447 0x7fffe3870581 
... <Mehr>