[Patch] OpenMP/Fortran: Support underscore variant of directive names

[Tobias Burnus]

I started to run into those in some testcases. Adding the feature
is simpler than to keep editing testcases :-)

(C/C++ support still needs to be added - and for compatibility
reasons it is recommended not to use this variant.)

Unless there are comments, I intent to commit this patch later today.

Tobias
-------------- next part --------------
A non-text attachment was scrubbed...
Name: underscore-dir.diff
Type: text/x-patch
Size: 8688 bytes
Desc: not available
URL: <https://gcc.gnu.org/pipermail/fortran/attachments/20260907/6193a8e0/attachment-0001.bin>