Building GSR with MSVC / qt5-static from source

[Prerequisites]
- Visual Studio 2019 (with Visual C++)
- Git / Perl / Python / Scons / maybe more?
    > NOTE: holy shit, Windows is much nicer when using scoop to install shit and manage your PATH (https://scoop.sh/)

[Environment Variables]
set CL=/MP
set QTDIR=C:\Qt\Qt-5.12.7
set PATH=%QTDIR%\bin;%PATH%

[Developer Command Prompt for VS 2019]     ; NOTE: defaults to x86 Native Tools Command Prompt for VS 2019 (i.e. 32-bit)
> git clone git://code.qt.io/qt/qt5.git
> cd qt5
> git checkout v5.12.7
> perl init-repository --module-subset=qtbase --branch
> cd ..
> mkdir qt5-static-v5.12.7
> cd qt5-static-v5.12.7
> ..\qt5\configure.bat -static -release -opensource -platform win32-msvc -confirm-license -nomake examples -nomake tests -nomake tools -opengl desktop -static-runtime
> nmake
     ; NOTE: this step, which builds qt5 from source will take a long time; a bit over 20 minutes on my Windows laptop
> nmake install
     ; installs static qt5 build to C:\Qt\Qt-5.12.7 (can be changed by adding '--prefix' to the configure.bat command)
> cd %GSR_ROOT%
     ; wherever the root directory for gambatte-speedrun is
> scripts\build_qt.bat
     ; for equivalent of build_qt.sh
     ; scripts\clean.bat for the equivalent of clean.sh

[TODO]
clean up SConstruct (shared/static library issue for msvc)
switch to cmake? (can seemingly meet all these needs, and maybe replace qmake, but annoying to change build system)