diff --git a/libc/bionic/pthread.c b/libc/bionic/pthread.c
index 92ee4aa..f294723 100644
--- a/libc/bionic/pthread.c
+++ b/libc/bionic/pthread.c
@@ -450,22 +450,18 @@
     return 0;
 }
 
-int pthread_attr_setstackaddr(pthread_attr_t * attr, void * stack_addr)
+int pthread_attr_setstackaddr(pthread_attr_t * attr __attribute__((unused)),
+                               void * stack_addr __attribute__((unused)))
 {
-#if 1
-    // It's not clear if this is setting the top or bottom of the stack, so don't handle it for now.
+    // This was removed from POSIX.1-2008, and is not implemented on bionic.
+    // Needed for ABI compatibility with the NDK.
     return ENOSYS;
-#else
-    if ((uint32_t)stack_addr & (PAGE_SIZE - 1)) {
-        return EINVAL;
-    }
-    attr->stack_base = stack_addr;
-    return 0;
-#endif
 }
 
 int pthread_attr_getstackaddr(pthread_attr_t const * attr, void ** stack_addr)
 {
+    // This was removed from POSIX.1-2008.
+    // Needed for ABI compatibility with the NDK.
     *stack_addr = (char*)attr->stack_base + attr->stack_size;
     return 0;
 }
@@ -513,7 +509,7 @@
     return 0;
 }
 
-int pthread_attr_setscope(pthread_attr_t *attr, int  scope)
+int pthread_attr_setscope(pthread_attr_t *attr __attribute__((unused)), int  scope)
 {
     if (scope == PTHREAD_SCOPE_SYSTEM)
         return 0;
@@ -523,7 +519,7 @@
     return EINVAL;
 }
 
-int pthread_attr_getscope(pthread_attr_t const *attr)
+int pthread_attr_getscope(pthread_attr_t const *attr __attribute__((unused)))
 {
     return PTHREAD_SCOPE_SYSTEM;
 }
@@ -1181,7 +1177,7 @@
 __LIBC_HIDDEN__
 int pthread_mutex_lock_impl(pthread_mutex_t *mutex)
 {
-    int mvalue, mtype, tid, new_lock_type, shared;
+    int mvalue, mtype, tid, shared;
 
     if (__unlikely(mutex == NULL))
         return EINVAL;
@@ -1275,7 +1271,7 @@
 __LIBC_HIDDEN__
 int pthread_mutex_unlock_impl(pthread_mutex_t *mutex)
 {
-    int mvalue, mtype, tid, oldv, shared;
+    int mvalue, mtype, tid, shared;
 
     if (__unlikely(mutex == NULL))
         return EINVAL;
@@ -1342,7 +1338,7 @@
 __LIBC_HIDDEN__
 int pthread_mutex_trylock_impl(pthread_mutex_t *mutex)
 {
-    int mvalue, mtype, tid, oldv, shared;
+    int mvalue, mtype, tid, shared;
 
     if (__unlikely(mutex == NULL))
         return EINVAL;
@@ -1437,7 +1433,7 @@
     clockid_t        clock = CLOCK_MONOTONIC;
     struct timespec  abstime;
     struct timespec  ts;
-    int               mvalue, mtype, tid, oldv, new_lock_type, shared;
+    int               mvalue, mtype, tid, shared;
 
     /* compute absolute expiration time */
     __timespec_to_relative_msec(&abstime, msecs, clock);
@@ -2118,9 +2114,7 @@
  */
 int  pthread_once( pthread_once_t*  once_control,  void (*init_routine)(void) )
 {
-    static pthread_mutex_t   once_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
     volatile pthread_once_t* ocptr = once_control;
-    pthread_once_t value;
 
     /* PTHREAD_ONCE_INIT is 0, we use the following bit flags
      *