The default "awk" there cannot handle some of the scripts
which are used by BDB for configuration.

The fix:
1) Introduce a variable "AWK" in some of the BDB shell scripts,
2) search "gawk" and give it precedence over "awk"
   when assigning a value to the "AWK" variable,
   fail if neither is found,
3) use that variable when calling an "awk" program with one
   of the critical scripts.

The perfect solution would be to use the "awk" program found
by "configure", but we cannot follow that approach because
BDB's configuration is handled as a special case before the
overall "configure" is run. Because of this,
1) the "configure" result isn't yet available,
2) "configure" will not handle these BDB files.
Searching "gawk" is a (not-so-nice) way out.

Note that all this need not be perfectly portable,
it is needed only when we create a source distribution tarball
from a develkopment tree.