enable static win64 MinGW builds
Add poor OpenMP scalability flag to --list=format-all-details

 Parallelized with OpenMP            yes
  Poor OpenMP scalability            no

(indented by 2 spaces, because it will only be listed for
formats with OpenMP support)
Merge pull request #490 from frank-dittrich/bleeding-jumbo

Add poor OpenMP scalability flag to --list=format-all-details