pgsql: Clean up local redeclarations of variables with DLLIMPORT, per

Log Message:
-----------
Clean up local redeclarations of variables with DLLIMPORT, per report
from Magnus that MSVC complains about this.

Modified Files:
--------------
pgsql/contrib/adminpack:
adminpack.c (r1.5 -> r1.6)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/adminpack/adminpack.c.diff?r1=1.5&r2=1.6)
pgsql/contrib/pg_buffercache:
pg_buffercache_pages.c (r1.9 -> r1.10)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_buffercache/pg_buffercache_pages.c.diff?r1=1.9&r2=1.10)
pgsql/contrib/pg_freespacemap:
pg_freespacemap.c (r1.8 -> r1.9)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pg_freespacemap/pg_freespacemap.c.diff?r1=1.8&r2=1.9)
pgsql/src/backend/catalog:
pg_proc.c (r1.140 -> r1.141)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/pg_proc.c.diff?r1=1.140&r2=1.141)
pgsql/src/backend/utils/misc:
guc.c (r1.356 -> r1.357)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c.diff?r1=1.356&r2=1.357)
pgsql/src/include:
miscadmin.h (r1.189 -> r1.190)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/miscadmin.h.diff?r1=1.189&r2=1.190)
pgsql/src/include/postmaster:
syslogger.h (r1.6 -> r1.7)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/postmaster/syslogger.h.diff?r1=1.6&r2=1.7)
pgsql/src/include/storage:
buf_internals.h (r1.87 -> r1.88)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/buf_internals.h.diff?r1=1.87&r2=1.88)
freespace.h (r1.23 -> r1.24)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/freespace.h.diff?r1=1.23&r2=1.24)
pgsql/src/include/utils:
guc.h (r1.75 -> r1.76)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/guc.h.diff?r1=1.75&r2=1.76)
pgsql/src/pl/plperl:
plperl.c (r1.120 -> r1.121)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/plperl.c.diff?r1=1.120&r2=1.121)
pgsql/src/pl/plpgsql/src:
pl_handler.c (r1.32 -> r1.33)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_handler.c.diff?r1=1.32&r2=1.33)