I never thought that I'd have to fix a string concatenation problem in
a BusyBox awk program to generate VT100 code in a container, but here we
are:

echo | awk 'END {print "foo" "" ++a, "foo" ++a}'

should output "foo0 foo1", and for all the ?awk I tested, it does,
except for BusyBox awk who thought funny to output "0 foo1", breaking the
teken_state.h file.