sudo apt-get install gcc-mingw-w64-x86-64 g++-mingw-w64-x86-64 wine64

  binutils-mingw-w64-x86-64 g++-mingw-w64-x86-64
  g++-mingw-w64-x86-64-posix g++-mingw-w64-x86-64-win32
  gcc-mingw-w64-base gcc-mingw-w64-x86-64
  gcc-mingw-w64-x86-64-posix gcc-mingw-w64-x86-64-posix-runtime
  gcc-mingw-w64-x86-64-win32 gcc-mingw-w64-x86-64-win32-runtime
  mingw-w64-common mingw-w64-x86-64-dev

x86_64-w64-mingw32-gcc -g -o hello hello.c
x86_64-w64-mingw32-g++ -g -o ch17q2s2 main.cpp

update-alternatives: using /usr/bin/x86_64-w64-mingw32-gcc-posix to provide /usr/bin/x86_64-w64-mingw32-gcc (x86_64-w64-mingw32-gcc) in auto mode
update-alternatives: using /usr/bin/x86_64-w64-mingw32-gcc-win32 to provide /usr/bin/x86_64-w64-mingw32-gcc (x86_64-w64-mingw32-gcc) in auto mode
update-alternatives: using /usr/bin/x86_64-w64-mingw32-g++-win32 to provide /usr/bin/x86_64-w64-mingw32-g++ (x86_64-w64-mingw32-g++) in auto mode

sudo apt install make wget tar zstd gpg
git clone https://github.com/HolyBlackCat/quasi-msys2
cd quasi-msys2/
make install _gtk4   # equivalent to `make install mingw-w64-x86_64-gtk4`

sudo apt install wine   # Optional.

# Install latest Clang
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh
rm llvm.sh

# Install more packages
make install _gcc _gdb    # We won't be using GCC, but we need libraries that come with it.

# Opens a new shell with the right environment variables configured.
env/shell.sh

# Notice `pkg-config` picking up the correct libraries.
win-clang++ hello_world.cpp `pkg-config --cflags --libs gtk4`
# This opens the app in Wine:
./a.exe

g++ -std=c++20 -O main.cpp