Thank you for the links.
I tried the  Revision 14205 of  openmpi.spec and it works for me only after some changes:
- in the mpivars-1.2.csh script part,
- and related to the line 330 in the original (14205) openmpi.spec:

eval "set %{configure_options}"

which will fail, if configure_options starts with --, in which case it will be interpreted as an option to set.
I attach the patch file.