If you're speaking about:
#elif (defined(__APPLE__) || defined(__MACOSX__)) && defined(_REENTRANT)
/* Latest XCode works with OpenMP, need to recheck here */
#undef LIBRAW_USE_OPENMP
This is not bug, but specially added because standard Apple toolchain does not support OpenMP
For other toolchains one may use -DLIBRAW_FORCE_OPENMP to enable this #if-branch:
#if defined(LIBRAW_FORCE_OPENMP)
...
If you're speaking about:
#elif (defined(__APPLE__) || defined(__MACOSX__)) && defined(_REENTRANT)
/* Latest XCode works with OpenMP, need to recheck here */
#undef LIBRAW_USE_OPENMP
This is not bug, but specially added because standard Apple toolchain does not support OpenMP
For other toolchains one may use -DLIBRAW_FORCE_OPENMP to enable this #if-branch:
#if defined(LIBRAW_FORCE_OPENMP)
...