Added support for POSIX reader-writer locks. Modified exp-drd/tests/filter-stderr such that i386 and AMD64 now generate the same output. Removed *.stderr.exp2 files. Added section that explains differences between LinuxThreads and NPTL to exp-drd/docs/README.txt. Made error message about LinuxThreads more clear. Made error messages more uniform.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@7531 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/exp-drd/drd_clientreq.c b/exp-drd/drd_clientreq.c
index 6ca6f7e..20d1aa3 100644
--- a/exp-drd/drd_clientreq.c
+++ b/exp-drd/drd_clientreq.c
@@ -30,6 +30,7 @@
 #include "drd_suppression.h"      // drd_start_suppression()
 #include "drd_thread.h"
 #include "drd_track.h"
+#include "drd_rwlock.h"
 #include "priv_drd_clientreq.h"
 #include "pub_tool_basics.h"      // Bool
 #include "pub_tool_libcassert.h"
@@ -214,24 +215,31 @@
       break;
 
    case VG_USERREQ__PRE_RWLOCK_INIT:
+      rwlock_pre_init(arg[1], arg[2]);
       break;
 
    case VG_USERREQ__POST_RWLOCK_DESTROY:
+      rwlock_post_destroy(arg[1]);
       break;
 
    case VG_USERREQ__PRE_RWLOCK_RDLOCK:
+      rwlock_pre_rdlock(arg[1], arg[2]);
       break;
 
    case VG_USERREQ__POST_RWLOCK_RDLOCK:
+      rwlock_post_rdlock(arg[1], arg[2]);
       break;
 
    case VG_USERREQ__PRE_RWLOCK_WRLOCK:
+      rwlock_pre_wrlock(arg[1], arg[2]);
       break;
 
    case VG_USERREQ__POST_RWLOCK_WRLOCK:
+      rwlock_post_wrlock(arg[1], arg[2]);
       break;
 
-   case VG_USERREQ__POST_RWLOCK_UNLOCK:
+   case VG_USERREQ__PRE_RWLOCK_UNLOCK:
+      rwlock_pre_unlock(arg[1]);
       break;
 
    default: