I attempted to backport your commit to drop use of union wait[1] to the Debian 8.1.9 package, but it causes the following build error (line numbers are relative to the 8.1.9 version):

../clients/qevent/qevent.c: In function ‘qevent_start_trigger_script’: ../clients/qevent/qevent.c:307:2: error: #endif without #if

#endif

../clients/qevent/Makefile:83: recipe for target 'qevent.o' failed make[2]: * [qevent.o] Error 1

The attached patch resolves the problem and also streamlines the surrounding ifdefs (otherwise essentially the same condition is being checked three times in a row)

1. ​https://gitlab.com/loveshack/sge/commit/538640ffe09a44a14d9f0047708f9c87d90c29ac

The changeset https://arc.liv.ac.uk/trac/SGE/changeset/20140406123948-0ed77-974278d41c87f2f53e735ad9d271fc2c211d3395/sge (Assume POSIX poll available) got rid of the conditional USE_POLL, but the changes to cl_commlib.c contained two glitches where #ifndef USE_POLL was treated like #ifdef USE_POLL, ie. the preprocessor directives were removed, but the enclosed code block was not. As a result, the releases 8.1.7 up to 8.1.9 impose a connection limit based on FD_SETSIZE, even though poll() is used instead of select(). The attached patch removes both leftover hunks from the original changeset, which means that connections are limited by resource constraints again, as they should be. It fixes connection problems in larger environments with 1000 or more hosts.

[Imported from gridengine issuezilla ​http://gridengine.sunsource.net/issues/show_bug.cgi?id=154]

        Issue #:      154              Platform:     All        Reporter: ernst (ernst)
       Component:     gridengine          OS:        All
     Subcomponent:    cleanup          Version:      5.3beta2      CC:    None defined
        Status:       NEW              Priority:     P3
      Resolution:                     Issue type:    TASK
                                   Target milestone: ---
      Assigned to:    ernst (ernst)
      QA Contact:     ernst
          URL:
       * Summary:     suppress READ_DANGLING (insure) in combination with getenv()
   Status whiteboard:
      Attachments:

     Issue 154 blocks:
   Votes for issue 154:


   Opened: Wed Feb 20 03:39:00 -0700 2002 
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sge_get_root_dir() and other function raise a READ_DANGLING error.

This should be handled properly, e.g. by strdupping the value returned by getenv()