Add interface for getting undefined function and variable info

[mplegendre]

As discussed, I've added an interface for fetching information about undefined functions and variables without going through Function callsite info. This builds off of @kupsch work on callsites, but helps with some situations with compilers (seen in gcc 10.2) aren't outputting callsite DWARF information, but they are outputting signatures for undefined symbols. This works by building up a list of undefined symbol names from the GOT, then when DWARF parsing it matches Type and Function signature info to those symbol names.

I was unable to get the Dyninst testsuite working, and I've only validated this against some out-of-testsuite tests.

[vsoch]

@mplegendre you need to rebase with dyninst master, you are missing the ABI tests!

• Here is your github workflows directory: https://github.com/mplegendre/dyninst/tree/parse-undefined/.github/workflows
• Here is what should be there: https://github.com/dyninst/dyninst/tree/master/.github/workflows

The testing suite has been pretty actively changed so it's going to likely influence results here.

[mplegendre]

@mplegendre you need to rebase with dyninst master, you are missing the ABI tests!

I'm merging into @kupsch's callsite branch, not master. It's building on that work, and I don't want to rush the callsite work into master before it's ready.

[vsoch]

ah ok. I don't think @hainest can give a proper review with the test suite in that case - any reason @kupsch can't update his branch to be in line with master?

[vsoch]

@mplegendre if we are going to use this in Smeagle, could you provide some documentation for the functions that should be used and replaced?

[kupsch]

@mplegendre, @vsoch there is now a branch kupsch/parse-callsites-preview-3 that is based on the tip of master. Rebase your branch to it, and the test problems should be fixed

[vsoch]

woot! Thank you @kupsch !

[vsoch]

@mplegendre the libabigail ABI tests are super baller you will like them.

[mplegendre]

I've rebased to parse-callsites-preview-3. That fixed the testsuite problems I was having.
A documentation commit will follow soon.

[vsoch]

Tests are running here (I changed the recipe so they would! #1247)