Spectrum Analyzer demo does not link when building statically

When building -static on Windows, the Spectrum Analyzer demo fails to link.

spectrumanalyser.obj : error LNK2019: unresolved external symbol "_declspec(dllimport) public: __thiscall FFTRealWrapper::FFTRealWrapper(void)" (imp??0FFTRealWrapper@@QAE@XZ) referenced in function "public: __thiscall SpectrumAnalyserThread::SpectrumAnalyserThread(class QObject *)" (??0SpectrumAnalyserThread@@QAE@PAVQObject@@@Z)

spectrumanalyser.obj : error LNK2019: unresolved external symbol "_declspec(dllimport) public: __thiscall FFTRealWrapper::~FFTRealWrapper(void)" (imp1FFTRealWrapper@@QAE@XZ) referenced in function "public: void * __thiscall FFTRealWrapper::`scalar deleting destructor'(unsigned int)" (_GFFTRealWrapper@@QAEPAXI@Z)

spectrumanalyser.obj : error LNK2019: unresolved external symbol "_declspec(dllimport) public: void __thiscall FFTRealWrapper::calculateFFT(float * const,float const * const)" (imp?calculateFFT@FFTRealWrapper@@QAEXQAMQBM@Z) referenced in function "public: void __thiscall SpectrumAnalyserThread::calculateSpectrum(class QByteArray const &,int,int)" (?calculateSpectrum@SpectrumAnalyserThread@@QAEXABVQByteArray@@HH@Z)

..\spectrum.exe : fatal error LNK1120: 3 unresolved externals