Restricting the MK404 build to gcc-7 is not a good idea, since gcc-7 is already not available in several newer distributions. Just pick the current gcc version. Current gcc 10 versions build MK404 correctly.
@@ -315,7 +315,7 @@ check_packages()
{
packages=(
"libelf-dev"
-"gcc-7"
+"gcc"
"gcc-avr"
"libglew-dev"
"freeglut3-dev"