Thread: pgsql: Detect and error out on inability to get proper linkage

Log Message:
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Detect and error out on inability to get proper linkage information required for plperl, usually due to absence of perl
ExtUtils::Embedmodule. Backpatch as far as 8.1. 

Modified Files:
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    pgsql:
        configure (r1.610 -> r1.611)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure?r1=1.610&r2=1.611)
    pgsql/config:
        perl.m4 (r1.3 -> r1.4)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/config/perl.m4?r1=1.3&r2=1.4)