* bjorn/fix-make/OTP-13855:
  make, ct_make: Handle warning attributes in source files

* raimo/gen_statem-callback_mode/OTP-13752:
  ssl: Upgrade suite testing skipped if stdlib upgrade is required
  Fix version numbers and dependencies

Conflicts:
	lib/ssl/src/ssl.appup.src
	lib/ssl/vsn.mk

epp learned to handle the -warning() directive in 14d72f02, but
make and ct_make were not updated to expect a {warning,_} return
value from epp:parse_erl_form/1.

The bug when introduced in OTP-19.0.

Optimize adding multiple modules to an Xref server

Extracting data from debug info in BEAM files is parallelized.

The speed-up is not outstanding. If memory is not an issue, adding
`{spawn_opt, [{min_heap_size, <large number>}]}' to the option list of
xref:start/2 can make a (small) difference.

Reading of modules from a directory is parallelized. Attempts to
parallelize all modules when adding a release have been rejected since
the gain showed to be small compared to the increased complexity of
the code.

Using a process for coordinating the reading has not been attempted.