pllolcode - pllolcode: Improve type conversion logic (well, make it more

Log Message:
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Improve type conversion logic (well, make it more responsive to different types, anyway; hopefully it's an improvement)

Modified Files:
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    pllolcode:
        DOC (r1.19 -> r1.20)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/DOC.diff?r1=1.19&r2=1.20)
        gram.y (r1.23 -> r1.24)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/gram.y.diff?r1=1.23&r2=1.24)
        pllolcode.c (r1.14 -> r1.15)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/pllolcode.c.diff?r1=1.14&r2=1.15)
        pllolcode.h (r1.18 -> r1.19)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/pllolcode.h.diff?r1=1.18&r2=1.19)
        pllolcode_symbol.c (r1.10 -> r1.11)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/pllolcode_symbol.c.diff?r1=1.10&r2=1.11)
        scan.l (r1.18 -> r1.19)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pllolcode/pllolcode/scan.l.diff?r1=1.18&r2=1.19)