install the private/v80.h header file

[tmancill]

Hi. I noticed this when attempting to build freeswitch. It looks like private/v80.h needs to be installed along with expose.h. The reference to private/v80.h was added in d8dfbd7.

making all mod_spandsp
make[4]: Entering directory '/tmp/sources/freeswitch/src/mod/applications/mod_spandsp'
  CC       mod_spandsp_la-mod_spandsp.lo
In file included from /usr/local/include/spandsp.h:154,
                 from mod_spandsp.h:50,
                 from mod_spandsp.c:39:
/usr/local/include/spandsp/expose.h:69:10: fatal error: spandsp/private/v80.h: No such file or directory
   69 | #include <spandsp/private/v80.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[4]: Leaving directory '/tmp/sources/freeswitch/src/mod/applications/mod_spandsp'

This PR also includes a tweak to autogen.h, which carps about the ./config directory that already exists. I'm happy to split that into a separate PR, or modify this one to remove the mkdir entirely. I'm not sure under what circumstance the directory wouldn't exist since it is part of the repo.

[freeswitch-ci-system]

Scan-build found bugs: https://public-artifacts.signalwire.cloud/drone/freeswitch/spandsp/60/index.html

[siadatism]

I got to the same problem when building freeswitch. Thank you @tmancill for the solution. Can this PR be accepted sooner so the master branch becomes usable in the freeswitch build? I saw CI errors and they are irrelevant to this PR.

[wangdong2023]

thank you for the solution.
All the tutorials I read didn't mention this, I guess it comes with recent changes (though this repo seems to be rather quite).
My first thought is to go back to previous versions, didn't find any tags or releases.

[markjcrane]

This is pull request is definitely needed for FreeSWITCH 1.10.10. Experienced the same problem.

Agreed that tags or releases would be really helpful.

[killdashnine]

Can confirm the same here. Also very much agree on tagging versions, it's now either pinning a specific commit or patching this manually.

[xrobau]

The missing include does break compilation of freeswitch, and this simple patch fixes it!

[xrobau]

Note that freeswitch itself ALSO needs fixes - see ticket

• spandsp defines and v18_init() function has changed since d9681c3747f signalwire/freeswitch#2282 and linked patch

xrobau/freeswitch-ubuntubuilder@492a713#diff-aa73d3346e8371c37fd4c51934f9b1902f459752244c32ddb7dea4a92af5ded8