auto: Remove unused pthread spinlock checks

auto/threads

@@ -73,56 +73,6 @@ if [ $nxt_found = no ]; then
 fi
 
 
-# FreeBSD, Solaris, AIX.
-
-nxt_feature="pthread spinlock"
-nxt_feature_name=NXT_HAVE_PTHREAD_SPINLOCK
-nxt_feature_run=yes
-nxt_feature_incs=
-nxt_feature_libs=$NXT_PTHREAD
-nxt_feature_test="#include <pthread.h>
-
-              int main(void) {
-                  pthread_spinlock_t  lock;
-
-                  if (pthread_spin_init(&lock, PTHREAD_PROCESS_PRIVATE) != 0)
-                      return 1;
-                  if (pthread_spin_lock(&lock) != 0)
-                      return 1;
-                  if (pthread_spin_unlock(&lock) != 0)
-                      return 1;
-                  if (pthread_spin_destroy(&lock) != 0)
-                      return 1;
-                  return 0;
-              }"
-. auto/feature
-
-
-if [ $nxt_found = yes ]; then
-
-    # Linux glibc uses 0 as pthread_spinlock_t initial value on the most
-    # platforms.  However, on i386 and x86_64 the initial value is 1.
-
-    nxt_feature="pthread spinlock zero initial value"
-    nxt_feature_name=NXT_HAVE_PTHREAD_SPINLOCK_ZERO
-    nxt_feature_run=yes
-    nxt_feature_incs=
-    nxt_feature_libs=$NXT_PTHREAD
-    nxt_feature_test="#include <pthread.h>
-
-                      pthread_spinlock_t  lock = 0;
-
-                      int main(void) {
-                          if (pthread_spin_trylock(&lock) != 0)
-                              return 1;
-                          if (pthread_spin_unlock(&lock) != 0)
-                              return 1;
-                          return 0;
-                      }"
-    . auto/feature
-fi
-
-
 nxt_feature="sem_timedwait()"
 nxt_feature_name=NXT_HAVE_SEM_TIMEDWAIT
 nxt_feature_run=yes