Log Message:
p5-DB_File: update to 1.842.

1.842 14 July 2018

   * Document the MaocOS build failures & how MacPort can work around th eissue.
     # 125238
     # 125585
     # RT 133280

   * Write all test db files into a directory created by File::Temp
     Protects against any possible races if running a parallel build.

   * #96357: DB_File destructor is not thread-safe
     Added CLONE_SKIP to DB_File.pm and included the test db-threads.t from the \ 
patch.
     Note - This only works with perl >= 5.8.7