Regarding srsRAN_Project build errors

[SurabhiKarandikar]

Dear all,
I am sharing fixes to some srsRAN_Project build errors due to C++ compiler version incompatibilities / version syntax issues. I spent almost 2 days fixing these errors, and I hope many of you may face these issues. Please do try out the solutions below, and it will save you a lot of time:
Changes done in srsRAN_Project codebase to avoid build errors:

1. remove 'constexp' keyword from lines 60 and 95 (pdsch_default_time_allocation.cpp)
2. remove all the [likely] / [unlikely] keywords from the file (HttpParser.h)
3. replace line 45 with: #define has_member(T, EXPR) detail::has_member_impl([](auto&& obj) -> decltype(obj.EXPR) { return obj.EXPR; }) ; in the file (has_member.h)
4. Edit the files with the changes attached (sib_pdu_assembler.h and sib_pdu_assembler.cpp)
5. Edit the files with the changes attached (srsran_scheduler_adaptor.h and srsran_scheduler_adaptor.cpp)

One more finding that I learnt, please keep a local repo with these changes, so that anytime you pull the recent srsRAN_Project repo, the changes can be easily copied from your repo.

Sincerely,
Surabhi Karandikar

[SurabhiKarandikar]

Please reach out to me for the modified files.