hdf5_der

[svn-r24454] Checkin for bug fix SWMR-11: used message file to coordinate test runs for h5watch.
The changes were initially done as part of the file locking implementation.

In addition, fixes for the following:
A) Bug fix when enable-production in test/tfile.c--
   --test_swmr_write(): use latest format in creating the test files

B) Bug fixes to sync up with revise_chksum_retry branch:
   1) test/accum.c--fix to use new_argv/new_envp for execve() and clean out compilation warnings
   2) hl/src/H5HLprivate2.h--put the defines in alphabetical order
   3) hl/tools/h5watch/h5watch.c--h5watch test exit code error due to error stack
   4) hl/tools/h5watch/extend_dset.c--clean up some compilation warnings

Tested on jam, ostrich, koala, platypus, emu, aix.