pgsql: Remove dllinit.c; it was only needed for long-obsolete Cygwin

Log Message:
-----------
Remove dllinit.c; it was only needed for long-obsolete Cygwin versions,
and there was some question about its copyright status.

Modified Files:
--------------
    pgsql/src:
        Makefile (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/Makefile.diff?r1=1.39&r2=1.40)
    pgsql/src/backend:
        Makefile (r1.115 -> r1.116)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/Makefile.diff?r1=1.115&r2=1.116)
    pgsql/src/makefiles:
        Makefile.cygwin (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/makefiles/Makefile.cygwin.diff?r1=1.8&r2=1.9)
        Makefile.win32 (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/makefiles/Makefile.win32.diff?r1=1.9&r2=1.10)

Removed Files:
-------------
    pgsql/src/utils:
        Makefile
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/utils/Makefile)
        dllinit.c
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/utils/dllinit.c)