Question about building static Qt mingw executables

I’m trying to build x2goclient with the mingw32 compiler. It uses Qt and I’d like to produce a static executable. I’m ending up with the following link line:

i686-w64-mingw32-g++ -g -fstack-protector -static -static-libstdc++ -static-libgcc -Wl,-subsystem,windows -mthreads -o release/x2goclient.exe @object_script.x2goclient.Release  -lssh.dll -lwinspool /usr/i686-w64-mingw32/sys-root/mingw/lib/libQt5Svg.dll.a /usr/i686-w64-mingw32/sys-root/mingw/lib/libQt5Widgets.dll.a /usr/i686-w64-mingw32/sys-root/mingw/lib/libQt5Gui.dll.a -lgdi32 -lcomdlg32 -loleaut32 -limm32 -luxtheme -ljpeg -lpng -lharfbuzz /usr/i686-w64-mingw32/sys-root/mingw/lib/libQt5Network.dll.a -lcrypt32 -ldnsapi -liphlpapi /usr/i686-w64-mingw32/sys-root/mingw/lib/libQt5Core.dll.a -lz -lpcre2-16 -lversion -lole32 -luuid -lwinmm -lws2_32 -ladvapi32 -lshell32 -luser32 -lkernel32 -lnetapi32 -luserenv -liconv release/x2goclient_res.o  -lmingw32 /usr/i686-w64-mingw32/sys-root/mingw/lib/libqt5main.a -lshell32 

Which as far as I can tell isn’t quite right - I think the static Qt libraries are libQt5Core.a, etc. not dll.a.

I’m specifying a static config to qmake and QT is specified in the x2goclient.pro simply with:

QT += svg network

Any guidance would be greatly appreciated.