Changes

buildsystem/regen_makefile: modernize

Apply various small changes to make this file more readable.

Change-Id: I5a7dcd6171c6a370928ebedafc5ed318384dd8dd

buildsystem/gen_links: move set -e to users

Make it more obvious that the various gen_links.sh scripts are running
with "set -e" by adding it to the #! line instead of setting it through
an included file.

Change-Id: I4caf445bef716161526a213d6a06ecc9d30f78cb

buildsystem/gen_links: rename ignore_pp_results

Rename ignore_pp_results to gen_links_finish in preparation for the next
patch where the function will be used for generating more symlinks
instead of writing to a gitignore file. This is a separate commit to
make the next one more readable.

Change-Id: I6a1a79f1a3ff18fe4b51e4c72c3e9b56c571935e

buildsystem: build out-of-tree

The buildsystem used to create symlinks to dependency source files in
the testsuite directories, and then building inside that source
directory. This lead to many unrelated files being in the source
directory.

Change the logic to create symlinks to all sources in a separate
$BUILDDIR instead (default: _build) and do the build there.

Advantages:
* Source directories are not cluttered with other files anymore.
* Clean up logic becomes much simpler and faster (rm -rf _build instead
  of generating a Makefile and running "make clean" in every testsuite
  directory).
* No need to generate gitignore files on the fly anymore.
* Using a separate $BUILDDIR is now possible, this will be used by
  testenv in a follow-up patch when running with podman, to make sure
  that build artifacts from podman and not using podman are not mixed as
  they are incompatible.

Related: OS#6599
Change-Id: If18aaf2a2a0d55bb617e5cb1b73f6ee4b1952494

buildsystem: make output more readable

Generate short and readable compile messages:

  CC       IPL4asp_PT.o
  CCLD     TCCInterface.so
  CCLD     TELNETasp_PT.so
  CCLD     MGCP_Test

Instead of the very verbose messages we would get otherwise. Especially
the linking message clutters a whole page of terminal output without
this path:

   if ... g++ ... $ALL_OBJ_FILES; then : ; else ... $ALL_OBJ_FILES; fi

Change-Id: I780106e64089dc24a7ba724f6a94e67417d49c30

testenv: remove copy_ttcn3_hacks_dir

When running with podman, set a separate builddir to avoid conflicts
with build objects generated from running "make" outside of podman. As
the buildsystem supports setting a differerent builddir directly now,
remove the copy_ttcn3_hacks_dir logic that was used to emulate this
feature.

Change-Id: I9cae0c4f8c34bb6876ef51048ef19b35a2e369a9

testenv: refactor run --until-nok code

Refactor the code in preparation for using the code that checks if the
testsuite was successful with a new --bisect arg in the next patch.

Change-Id: I3a8fc83c6833f0d2a8be9c0d7ddaea0546859988

testenv: run: add --bisect argument

Add an argument that lets testenv.py exit with != 0 when at least one
test has failed, so it can be used with "git bisect".

Change-Id: I941064c1c704560e0f7351c82e810481cd72b6da

start-testsuite: fix passing $TEST to ttcn3_start

Fix that testenv / ttcn3_start kept running after the testsuites were
already done. This was caused by passing an empty string to ttcn3_start
as test argument, which causes it to still use the config file, but run
in a single test mode:

https://gitlab.eclipse.org/eclipse/titan/titan.core/-/blob/9.0.0/mctr2/mctr/ttcn3_start#L307-319

After the first test ran, ttcn3_start sends "emtc" to the MTC, which
replies with "MTC cannot be terminated." as it is still in
MC_EXECUTING_TESTCASE instead of MC_READY:

https://gitlab.eclipse.org/eclipse/titan/titan.core/-/blob/9.0.0/mctr2/cli/Cli.cc#L695-700

The ttcn3_start script then waits forever for the "MTC terminated.."
string, which doesn't come since "emtc" isn't sent to the MTC a second
time:

https://gitlab.eclipse.org/eclipse/titan/titan.core/-/blob/9.0.0/mctr2/mctr/ttcn3_start#L353-356

Fixes: 050ba48c ("buildsystem: build out-of-tree")
Change-Id: Ic50de8350e20d101417c5689058b64fe6547126f