pgsql: Squelch some VC++ compiler warnings.

Log Message:
-----------
Squelch some VC++ compiler warnings. Mark float literals with the "f"
suffix, to distinguish them from doubles. Make some function declarations
and definitions use the "const" qualifier for arguments consistently.
Ignore warning 4102 ("unreferenced label"), because such warnings
are always emitted by bison-generated code. Patch from Magnus Hagander.

Modified Files:
--------------
    pgsql/contrib/intarray:
        _int.h (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int.h.diff?r1=1.11&r2=1.12)
    pgsql/contrib/pg_trgm:
        trgm_op.c (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_trgm/trgm_op.c.diff?r1=1.5&r2=1.6)
    pgsql/contrib/tsearch2:
        rank.c (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/rank.c.diff?r1=1.21&r2=1.22)
    pgsql/src/include:
        pg_config.h.win32 (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.win32.diff?r1=1.39&r2=1.40)
    pgsql/src/interfaces/libpq:
        fe-secure.c (r1.90 -> r1.91)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-secure.c.diff?r1=1.90&r2=1.91)
        libpq-int.h (r1.117 -> r1.118)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/libpq-int.h.diff?r1=1.117&r2=1.118)
    pgsql/src/timezone:
        ialloc.c (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/timezone/ialloc.c.diff?r1=1.7&r2=1.8)
        zic.c (r1.19 -> r1.20)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/timezone/zic.c.diff?r1=1.19&r2=1.20)
    pgsql/src/tools/msvc:
        Project.pm (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/Project.pm.diff?r1=1.7&r2=1.8)
        mkvcbuild.pl (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/mkvcbuild.pl.diff?r1=1.11&r2=1.12)