Makefile: Do not remote scheme/termios/ anymore

Signed-off-by: Frank Terbeck <ft@bewatermyfriend.org>
Makefile: Clean up scheme/test/ as well

Signed-off-by: Frank Terbeck <ft@bewatermyfriend.org>
Makefile: tests: Set GUILE_ and PERL_BINARY explicitly

Signed-off-by: Frank Terbeck <ft@bewatermyfriend.org>