Priority inherance issue

Ok
Have to said, it is getting complicated :)

Follow-Ups:
- Priority inherance issue
  - From: chrisj at rtems.org (Chris Johns)

References:
- Priority inherance issue
  - From: manuel.coutinho at edisoft.pt (Manuel Coutinho)
- Priority inherance issue
  - From: aitor.viana.sanchez at esa.int (Aitor Viana)
- Priority inherance issue
  - From: hiyangxi at gmail.com (xi yang)
- Priority inherance issue
  - From: manuel.coutinho at edisoft.pt (Manuel Coutinho)
- Priority inherance issue
  - From: hiyangxi at gmail.com (xi yang)
- Priority inherance issue
  - From: manuel.coutinho at edisoft.pt (Manuel Coutinho)
- Priority inherance issue
  - From: hiyangxi at gmail.com (xi yang)