Log Message:
Update tex-metapost{,-doc} to 1.212.

Changes:

* MetaPost now adheres to the openin_any / openout_any settings in
   texmf.cnf

* In some cases 'readfrom' made the file's path be prepended to the
   actually read string from the file.

* The 'prologues:=3 output' with embedded labels was unreliable,
   especially when the resulting eps was included into a TeX document
   via dvips.

* 'newinternal numeric' has been fixed, it generated an error in
   metapost 1.211.

* Label regeneration sometimes failed to run when the file time stamps
   were close together.

* Reallocation of the string pool during output file name creation
   ('outputtemplate') could cause corruption in the created file's name.