The test for remaining DBG1 macros (added in
 d7b9e9ab) incorrectly exited with
non-zero status and caused the cleanup.sh script to abort.

(cherry picked from commit 76d9bb10)

Remove comments like
 /* foo(bar); */
and
 /* foo->bar = baz; */
and
 /* foo = bar->baz; */

This doesn't get rid of all dead code. As usual the result was visually
checked for false positives to ensure that no accidental content
removals occurred.

(cherry picked from commit f2d0a35a)

(cherry picked from commit 3e916da0)

(cherry picked from commit 19e2c765)

(cherry picked from commit 2c06691d)

(cherry picked from commit 4380d741)

- move it to the cleanup directory
- let it build the bundled ccmtcnvt utility
- organise related steps into sections