have_sys_socket.c: support for MacOS added

[vasiliyk]

Added support for MacOS:

1. CMakeList.txt: check if system is MacOS or Unix/Linux and set "SUPPORT_DISALLOW_SIGNAL_DURING_SENDING"
2. config.h.in: set SUPPORT_DISALLOW_SIGNAL_DURING_SENDING to be accessible for C preprocessor.
3. socket.h: if SUPPORT_DISALLOW_SIGNAL_DURING_SENDING is defined set "config_disallow_signal_during_sending_flag" flag to "SO_NOSIGPIPE" or "MSG_NOSIGNAL"
4. updated "sys_socket_sendto_tcp_target" and "sys_socket_sendto_udp_target" procedures of have_sys_socket.c to use flag config_disallow_signal_during_sending_flag

[goatshriek]

This is almost there, just one change outlined below to use CMake's check_symbol_exists function to instead determine what symbols are available for use, so that the platform detection doesn't become as much of a dependency for this to work as intended.

[vasiliyk]

Joel, thank you for review. The code is updated based on your comments.

[vasiliyk]

Joel, the code was updated based on the last recommendations. Thank you!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.60%. Comparing base (1d2df58) to head (d4664e3).
Report is 3 commits behind head on latest.

Additional details and impacted files

@@            Coverage Diff             @@
##           latest     #470      +/-   ##
==========================================
+ Coverage   90.59%   90.60%   +0.01%     
==========================================
  Files          47       47              
  Lines        4379     4385       +6     
  Branches      587      587              
==========================================
+ Hits         3967     3973       +6     
  Misses        279      279              
  Partials      133      133              

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[goatshriek]

Thanks for sticking with this one! There is just one last change needed - an include sys/socket.h is needed for the wrapped symbols, which is why the static analyzer has failed. It would probably be best to move the wrapper #defines to include/private/config/have_sys_socket.h to ensure this header is available for include, but I can take care of this later if you'd prefer to be done. At a minimum, adding this include should resolve the static analysis errors.

[vasiliyk]

Joel, I added sys/socket.h include to include/private/config/have_sys_socket.h as you suggested.

[goatshriek]

Sorry, I should have also mentioned that you'll need to move the code from ...wrapper/socket.h to have_sys_socket.h as well.

[vasiliyk]

No problem, I have moved the definition of config_disallow_signal_during_sending_flag from ...wrapper/socket.h to have_sys_socket.h as well.

[goatshriek]

Just one more failing check now - there is an include that is no longer necessary with the last refactoring. I believe once you take out this line it should be good to go.

Thanks again for your patience with this!

[vasiliyk]

Joel, I have removed unnecessary include.

[goatshriek]

Thanks very much for not only raising this issue but putting together a fix and sticking with it through the review process! Portability is a primary goal of this project and it's always great to see progress made towards that.