pthread rdwr locks

[Howard Chu]

I just noticed that we're explicitly disabling support for native rdwr 
locks in ldap_int_thread.h, and it's been that way since 2000. Any 
reason not to use the native locks instead of our emulation routines?

--
 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/