Add build script and workflow to validate API headers in C++

[jphickey]

Is your feature request related to a problem? Please describe.
As noted in issue #1365, there is currently no tests to check compatibility of the OSAL API with C++. Although C++ is not an officially targeted platform for OSAL, some users do have C++ code and occasionally the OSAL header files are included from C++ code.

Describe the solution you'd like
This is two parts:

1. All public OSAL headers should have an conditional extern "C" to handle the case if/when they are included from a C++ file.
2. There should be a workflow check to confirm that the API header files for OSAL are compliant with C++ 03.

Describe alternatives you've considered
The only other workaround is to insist that the user never include OSAL headers directly from C++, instead provide their own C++ wrapper for the OSAL API. But this is a fairly big thing when a few minor updates can make the OSAL headers more C++-friendly.

Additional context
Note that C++ would still be considered a secondary target here - a workflow can do some simple checks to at least make sure the headers don't contain any declarations that are outright incompatible with C++, but otherwise C++ support would be totally on the user to validate.

Notably - none of the unit tests run in C++.

Requester Info
Joseph Hickey, Vantage Systems, Inc.