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.
