I found the “bug”. There is a missing line in the mingw qmake configuration.
Add following line to “mkspecswin32-g++qmake.conf”:
QMAKE_RCC = $$[QT_INSTALL_BINS]$${DIR_SEPARATOR}rcc.exe
… and all will work!
找到4.8.3\mkspecs\win32-g++\qmake.conf 配置文件
QMAKE_EXT_OBJ = .o
QMAKE_EXT_RES = _res.o
QMAKE_RCC = $$[QT_INSTALL_BINS]$${DIR_SEPARATOR}rcc.exe
QMAKE_CC = $${CROSS_COMPILE}gcc
重新編譯即可