Currently, Cactus disables OpenMP collapse due to compiler problems either when specified explicitly in the option list, or when finding certain compilers that are known to have this kind of problem. However, the latter is only done for C and C++, but not Fortran. In addition, Cactus aborts compilation if collapse is not explicitly disabled, but affected compilers are found, with a message that collapse is disabled for C, but not for Fortran, indicating an error in the option list. While the first is true since Cactus actually disabled the collapse sections because it found a faulty compiler, the latter is not, since the option list doesn't mention collapse sections at all and isn't inconsistent.
This means in the end that the auto-detections isn't really working in the way that is was intended: that Cactus does things automatically if faulty compilers are found. Instead, Cactus currently aborts, with a message that isn't leading users in the right direction. A workaround right now is to define CCTK_DISABLE_OMP_COLLAPSE for both C and Fortran in the option list.
The proposed patch removes this error message, and instead adds the same compiler-detection for Fortran, that is already present for C and C++. The advantage would be that option lists wouldn't need to define anything. Cactus would either disable the collapse sections for all languages, or for none.
If accepted, I propose to backport this change, in addition to applying it to the development version. The patch was created using ET_2013_05.