Log Message:
-----------
Add SGML Makefile rule for single-page text, postgres.txt.
Modified Files:
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pgsql/doc/src/sgml:
Makefile (r1.145 -> r1.146)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/Makefile?r1=1.145&r2=1.146)