pgsql: Code coverage testing with gcov.

Log Message:
-----------
Code coverage testing with gcov.  Documentation is in the regression test
chapter.

Author: Michelle Caisse <Michelle.Caisse@Sun.COM>

Modified Files:
--------------
    pgsql:
        GNUmakefile.in (r1.47 -> r1.48)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/GNUmakefile.in?r1=1.47&r2=1.48)
        configure (r1.604 -> r1.605)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure?r1=1.604&r2=1.605)
        configure.in (r1.565 -> r1.566)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure.in?r1=1.565&r2=1.566)
    pgsql/doc/src/sgml:
        installation.sgml (r1.312 -> r1.313)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/installation.sgml?r1=1.312&r2=1.313)
        regress.sgml (r1.59 -> r1.60)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/regress.sgml?r1=1.59&r2=1.60)
    pgsql/src:
        Makefile.global.in (r1.242 -> r1.243)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/Makefile.global.in?r1=1.242&r2=1.243)
    pgsql/src/backend:
        common.mk (r1.7 -> r1.8)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/common.mk?r1=1.7&r2=1.8)