The zxspec48-app is an empty SDCC application template for ZX Spectrum 48K.
Add your .c and .s source files into the src directory and run
make
This will create the app.bin inside your build folder.
Pass the APP and ADDR parameters to change the name of your application and compile it to a different address.
make APP=myapp ADDR=0x9000`
There is a .vscode inside this repository. And if you press F5 it will run fuse emulator and you program in it. But to allow docker to access X Windows you need to execute
xhost +SI:localuser:$(whoami)