pgsql: Add additional rules so that make init-po for ecpg gets up to

Log Message:
-----------
Add additional rules so that make init-po for ecpg gets up to date flex and
bison output.  Without these, make can sometimes be tempted to invoke its
built-in rules using lex and yacc, which can fail if those commands are not
available.

This was a main cause for the NLS web site breakage.

Modified Files:
--------------
    pgsql/src/interfaces/ecpg:
        nls.mk (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/nls.mk?r1=1.1&r2=1.2)