Update:

This small example can also reproduce these compiler errors:
Qt Code: 
  1. #include <iostream>
  2. #include <libnova/utiltiy.h>
  3.  
  4. int main() { return 0; }
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Errors occure, because <iostream> also includes <pthread.h> somewhere down the road. And <pthread.h> has this funny stuff in it:

Qt Code: 
  1. #undef gmtime_r
  2. #define gmtime_r(_Time,_Tm)     ({ struct tm *___tmp_tm;                \
  3.                                                 pthread_testcancel();   \
  4.                                                 ___tmp_tm = gmtime((_Time)); \
  5.                                                 if (___tmp_tm) {        \
  6.                                                   *(_Tm) = *___tmp_tm;  \
  7.                                                   ___tmp_tm = (_Tm);    \
  8.                                                 }                       \
  9.                                                 ___tmp_tm;      })
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Then comes <libnova/utility.h> and declares:

Qt Code: 
  1. struct tm *gmtime_r (time_t *t, struct tm *gmt);
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When I include <libnova/utility.h> first, it will compile sucessfully. But being forced to include headers in a specific order feels very wrong. At least in this case. And it may not be possible in a very big project.

Is this a bug in the C library provided with MinGW?
What's the best way to handle this? For the time being, I could surround the conflicting declaratioin in <libnova/utility.h> with #ifndef...#endif.

Any advice?