Clean up the handling of "server" and "client" directories, while still avoiding the double listing of
common directories in 'SUBDIRS' macro ("make distclean" had failed due to that).
Solves bug#7368: "regex make error in 4.1.8"


BitKeeper/etc/ignore:
  Added ndb/include/ndb_version.h ndb/include/ndb_global.h to the ignore list
Makefile.am:
  Build the 'SUBDIRS' list from the new variable 'sql_union_dirs', not the old "client" and "servers" lists which will overlap.
  That overlap worked for build runs, but it caused failures of 'make distclean' etc because the overlapping directories
  were cleaned twice which could not work.
  Solves bug#7368: "regex make error in 4.1.8"
configure.in:
  Introduce a new variable 'sql_union_dirs' to contain those directories which are needed for either server or client.
  This is needed to have complete "server" and "client" directory lists in 'Makefile' but prevent double listing
  in 'SUBDIRS' (see the comment for 'Makefile.am').
  Solves bug#7368: "regex make error in 4.1.8"