$AUTOMAKE --add-missing
./configure COND=true
-$MAKE 2>stderr || { cat stderr >&2; exit 1; }
-cat stderr >&2
+run_make -E
grep 'overriding commands' stderr && exit 1
$MAKE sure-exist
./prog1 && exit 1
$MAKE distclean
./configure COND=false
-$MAKE 2>stderr || { cat stderr >&2; exit 1; }
-cat stderr >&2
+run_make -E
grep 'overriding commands' stderr && exit 1
./prog1
./sub/prog2