Massimo patches

I have patched up gram.y by adding a mention of UNLISTEN at the top of
gram.y.  I have also commented out the compile of ecpg because it does
not compile.

When we get Massimo's fixes, I will back these out.  I wanted the tree
to compile for my changes I am committing now.

--
Bruce Momjian                          |  830 Blythe Avenue
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