The Moc does not output file but it does output to the terminal screen if no -o is given. However MOC for 32 bits qt 5.1.0 works and moc for 4.8.4
I did notice that MOC for 32 bits qt 5.1.0 uses absolute path for include of the .h usign the QOBJECT.
When I redirect output for MOC 5.1.0 64 bits ( > somefile.cpp) and then compare it to the generated one from MOC 5.1.0 32 bits, there is that only difference already described (absolute vs relative path)

Here is the MOC generated by the Visual Studio add-in

"$(QTDIR)\bin\moc.exe" "%(FullPath)" -o ".\GeneratedFiles\$(ConfigurationName)\moc_%(Filename).cpp" -DUNICODE -DWIN32 -DQT_DLL -DQT_CORE_LIB -DQT_GUI_LIB -DQT_OPENGL_LIB -DQT_WIDGETS_LIB "-I.\GeneratedFiles" "-I." "-I$(QTDIR)\include" "-I.\GeneratedFiles\$(ConfigurationName)\." "-I$(QTDIR)\include\QtCore" "-I$(QTDIR)\include\QtGui" "-I$(QTDIR)\include\QtOpenGL" "-I$(QTDIR)\include\QtWidgets"

which translate to

"C:\Qt\qt5\qt5x64\qtbase\bin\moc.exe" "C:\DSPLAB_ORTEGA\QTApp\QTGLANAV2013\QTGLANAV2013\qtglanav2013.h" -o ".\GeneratedFiles\Debug\moc_qtglanav2013.cpp" -DUNICODE -DWIN32 -DQT_DLL -DQT_CORE_LIB -DQT_GUI_LIB -DQT_OPENGL_LIB -DQT_WIDGETS_LIB "-I.\GeneratedFiles" "-I." "-IC:\Qt\qt5\qt5x64\qtbase\include" "-I.\GeneratedFiles\Debug\." "-IC:\Qt\qt5\qt5x64\qtbase\include\QtCore" "-IC:\Qt\qt5\qt5x64\qtbase\include\QtGui" "-IC:\Qt\qt5\qt5x64\qtbase\include\QtOpenGL" "-IC:\Qt\qt5\qt5x64\qtbase\include\QtWidgets"