pgsql: I have added these macros to c.h: #define HIGHBIT

Log Message:
-----------
I  have added these macros to c.h:

        #define HIGHBIT                 (0x80)
        #define IS_HIGHBIT_SET(ch)      ((unsigned char)(ch) & HIGHBIT)

and removed CSIGNBIT and mapped it uses to HIGHBIT.  I have also added
uses for IS_HIGHBIT_SET where appropriate.  This change is
purely for code clarity.

Modified Files:
--------------
    pgsql/src/backend/access/common:
        heaptuple.c (r1.104 -> r1.105)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/heaptuple.c.diff?r1=1.104&r2=1.105)
    pgsql/src/backend/parser:
        scansup.c (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/scansup.c.diff?r1=1.30&r2=1.31)
    pgsql/src/backend/utils/adt:
        network.c (r1.56 -> r1.57)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/network.c.diff?r1=1.56&r2=1.57)
        varbit.c (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/varbit.c.diff?r1=1.47&r2=1.48)
    pgsql/src/backend/utils/mb:
        conv.c (r1.56 -> r1.57)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/conv.c.diff?r1=1.56&r2=1.57)
        wchar.c (r1.50 -> r1.51)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/wchar.c.diff?r1=1.50&r2=1.51)
    pgsql/src/backend/utils/mb/conversion_procs/euc_cn_and_mic:
        euc_cn_and_mic.c (r1.10 -> r1.11)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/conversion_procs/euc_cn_and_mic/euc_cn_and_mic.c.diff?r1=1.10&r2=1.11)
    pgsql/src/backend/utils/mb/conversion_procs/euc_kr_and_mic:
        euc_kr_and_mic.c (r1.10 -> r1.11)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/conversion_procs/euc_kr_and_mic/euc_kr_and_mic.c.diff?r1=1.10&r2=1.11)
    pgsql/src/backend/utils/mb/conversion_procs/euc_tw_and_big5:
        euc_tw_and_big5.c (r1.10 -> r1.11)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c.diff?r1=1.10&r2=1.11)
    pgsql/src/backend/utils/mb/conversion_procs/utf8_and_iso8859_1:
        utf8_and_iso8859_1.c (r1.12 -> r1.13)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/conversion_procs/utf8_and_iso8859_1/utf8_and_iso8859_1.c.diff?r1=1.12&r2=1.13)
    pgsql/src/include:
        c.h (r1.192 -> r1.193)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/c.h.diff?r1=1.192&r2=1.193)
    pgsql/src/include/utils:
        varbit.h (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/varbit.h.diff?r1=1.21&r2=1.22)
    pgsql/src/port:
        pgstrcasecmp.c (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/pgstrcasecmp.c.diff?r1=1.5&r2=1.6)