On UNIX here are a couple ways to create such a file:
ls *.ads *.adb *.sep > my_project.lst
find . -name “*.ads *.adb *.sep” -print > my_project.lst
In a Windows command shell:
dir /b *.ads *.adb > my_project.lst
dir /b /s *.ads *.adb > my_project.lst