5.1-related fixes
libmysqld/Makefile.am fixed to recompile and link ha_*.cc files that
keep dependance on THD structure.
Minor fixes to make tests working.


config/ac-macros/plugins.m4:
  condition_dependent_plugin_objects added
libmysqld/Makefile.am:
  rules for ha_*.o files added
  condition_dependent_plugin_objects sent to linker
libmysqld/lib_sql.cc:
  ddl_log initialization added
mysql-test/r/flush_block_commit_notembedded.result:
  result fixed
mysql-test/t/crash_commit_before.test:
  doesn't work in embedded server
mysql-test/t/csv.test:
  replace_result added
mysql-test/t/ps.test:
  doesn't work in embedded server
  should be fixed by separating ps_notembedded.test
mysql-test/t/ps_1general.test:
  replace_result fixed
mysql-test/t/ps_not_windows.test:
  doesn't work in embedded server
mysql-test/t/trigger.test:
  replace_result fixed
sql/sql_insert.cc:
  #ifdef HAVE_ROW_BASED_REPLICATION added
storage/myisam/ha_myisam.cc:
  MY_UNPACK_FILENAME flag added