Bitcoin QT - why do I have an undefined reference to `qInitResources_bitcoin() error
The root cause of the error is likely related to the Qt Resource Compiler (rcc), which is generally called earlier as part of the bitcoin compilation process. The rcc generates the src/qt/qrc_bitcoin.cpp file from the src/qt/bitcoin.qrc resource file.
Unfortunately, the compilation process is not halted, if the rcc encounters an error when operating on the resource file. Instead an empty src/qt/qrc_bitcoin.cpp file is created. qInitResources_bitcoin() is never defined and hence will be missing during the linking process.
A common source of errors are missing assets in the qt makefile (ensure listed assets in src/qt/bitcoin.qrc are also included in src/Makefile.qt.include.