Implement pthread_rwlock functions for NaCl newlib.

src/untrusted/pthread/nc_thread.c

Index: src/untrusted/pthread/nc_thread.c
diff --git a/src/untrusted/pthread/nc_thread.c b/src/untrusted/pthread/nc_thread.c
index 332dc099555487e009fed5c39cd9cd33cec51d4a..edf645c90e49687ad57e7547402a6cefe81eec99 100644
--- a/src/untrusted/pthread/nc_thread.c
+++ b/src/untrusted/pthread/nc_thread.c
@@ -94,7 +94,7 @@ int __nc_memory_block_counter[2];
 
 /* Internal functions */
 
-static inline nc_thread_descriptor_t *nc_get_tdb(void) {
+struct nc_thread_descriptor *__nc_get_tdb(void) {
   /*
    * Fetch the thread-specific data pointer.  This is usually just
    * a wrapper around __libnacl_irt_tls.tls_get() but we don't use
@@ -105,7 +105,7 @@ static inline nc_thread_descriptor_t *nc_get_tdb(void) {
 }
 
 static void nc_thread_starter(void) {
-  nc_thread_descriptor_t *tdb = nc_get_tdb();
+  nc_thread_descriptor_t *tdb = __nc_get_tdb();
   __newlib_thread_init();
 #if defined(NACL_IN_IRT)
   g_is_irt_internal_thread = 1;
@@ -243,6 +243,7 @@ static void nc_tdb_init(nc_thread_descriptor_t *tdb,
   tdb->tls_base = tdb;
   tdb->joinable = PTHREAD_CREATE_JOINABLE;
   tdb->join_waiting = 0;
+  tdb->rdlock_count = 0;
   tdb->stack_node = NULL;
   tdb->tls_node = NULL;
   tdb->start_func = NULL;
@@ -304,7 +305,7 @@ void __nc_initialize_unjoinable_thread(struct nc_combined_tdb *tdb) {
 void __pthread_initialize(void) {
   __pthread_initialize_minimal(TDB_SIZE);
 
-  struct nc_combined_tdb *tdb = (struct nc_combined_tdb *) nc_get_tdb();
+  struct nc_combined_tdb *tdb = (struct nc_combined_tdb *) __nc_get_tdb();
   nc_tdb_init(&tdb->tdb, &tdb->basic_data);
   __nc_initial_thread_id = &tdb->basic_data;
 
@@ -492,7 +493,7 @@ void pthread_cleanup_pop(int execute) {
 
 void pthread_exit(void *retval) {
   /* Get all we need from the tdb before releasing it. */
-  nc_thread_descriptor_t    *tdb = nc_get_tdb();
+  nc_thread_descriptor_t    *tdb = __nc_get_tdb();
   nc_thread_memory_block_t  *stack_node = tdb->stack_node;
   int32_t                   *is_used = &stack_node->is_used;
   nc_basic_thread_data_t    *basic_data = tdb->basic_data;
@@ -630,7 +631,7 @@ int pthread_kill(pthread_t thread_id,
 
 pthread_t pthread_self(void) {
   /* Get the tdb pointer from gs and use it to return the thread handle. */
-  nc_thread_descriptor_t *tdb = nc_get_tdb();
+  nc_thread_descriptor_t *tdb = __nc_get_tdb();
   return tdb->basic_data;
 }