remove brain-dead rule that double quotes are needed if and only if the
datatype is pass-by-reference; neither direction of the implication holds
water.  Instead, examine the actual data string to see if it contains
any characters that force us to quote it.
Add some documentation about quoting of array values, which was previously
explained nowhere AFAICT.

  produces garbage.

I learned the hard way that

        #if UNDEFINED_1 == UNDEFINED_2
        #error "gcc is idiot"
        #endif

prints "gcc is idiot" ...

Affected are MD5/SHA1 in internal library, and also HMAC-MD5/HMAC-SHA1/
crypt-md5 which use them.  Blowfish is ok, also Rijndael on at
least x86.

Big thanks to Daniel Holtzman who send me a build log which
contained warning:

        md5.c:246: warning: `X' defined but not used

Yes, gcc is that helpful...

Please apply this.

--
marko

already addressed by previous doc updates.

potential problems discussed in pgsql-interfaces.

never did inflateEnd, thus leaking some tens of KB per call.  Which
added up *real fast* when dealing with, say, thousands of BLOBs.
Thanks to Lane Rollins for the bug report.