configure.ac: use AC_PATH_TOOL for nm

[nwf]

nm might, especially in cross-compilation scenarios, be available but prefixed with the target triple. So: use AC_PATH_TOOL rather than AC_PATH_PROG to find it. (See https://www.gnu.org/software/autoconf/manual/autoconf-2.68/html_node/Generic-Programs.html .)

Found and proposed fix tested by cross-compiling Asterisk using Nixpkgs on x86_64 targeting aarch64. :)

[sangoma-oss-cla]

All committers have signed the CLA.

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[jcolp]

The Asterisk project commits a generated configure script to make it easy for users. You will need to regenerate using bootstrap.sh and include the regenerated configure script in this change.

[jcolp]

The PR check also needs to be fulfilled and branches specified.

[nwf]

Running ./bootstrap.sh on 5d15a42 makes changes to ./configure. I've pulled those out to a commit prior to my change, and then ran ./bootstrap.sh again after AC_PATH_TOOL-ization of nm as a 3rd commit. Please feel free to squash appropriately, or tell me that I have done something wrong because the first of those should be empty.

[jcolp]

Squash it all down to one commit, it's fine.

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[gtjoseph]

cherry-pick-to: 22
cherry-pick-to: 20

[gtjoseph]

@nwf This PR has been sitting for a while. If you want it merged, you need to fix the commit message and PR description so they match.

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Workflow PRCPCheck failed
Setup: cherryPick.sh: Unable to cherry-pick commit 'configure.ac: use AC_PATH_TOOL for nm' to branch 23

[gtjoseph]

This PR doesn't cherry-pick cleanly to the 23 branch although it does cherry-pick cleanly to 22 and 20. You're going to need to do the following...

Edit the cherry-pick-to comment in this PR and remove the cherry-pick-to: 23 line.

In your development repo...

$ git checkout 23
$ git cherry-pick 2228239998f06185fec21
# It's going to fail but that's OK.
$ git add configure
# configure will be invalid but that's OK.
$ git cherry-pick --continue
$ ./bootstrap.sh
# configure will now be regenerated.
$ git commit -a --amend --no-edit
# Create a new PR just for 23.
$ gh pr create --fill --base 23

Now add a `cherry-pick-to: none` comment to the new PR.

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Workflow PRCPCheck failed
20-pjs1: FAILED TEST: channels/pjsip/headers/non_anonymous_from_basic_call

[github-actions]

Successfully merged to branch master and cherry-picked to ["22","20"]