[PATCH v3.1] BFD: remove unused spinlock

[Zhang Maiyun]

The only use of the spinlock in `struct bfd_proto` was removed in 38acb415f
and now it should be fine to remove it.

The check for `pthread_spin*` in `aclocal.m4` is also removed
accordingly. This makes it possible to port BFD support to platforms
without spinlocks (e.g. Darwin)

Signed-off-by: Zhang Maiyun <me at maiyun.me>
---
 aclocal.m4      | 4 ++--
 proto/bfd/bfd.h | 2 --
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index dd5cca35..7fc9c995 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -91,8 +91,8 @@ AC_DEFUN([BIRD_CHECK_PTHREADS],
 	    [
 	      pthread_t pt;
 	      pthread_create(&pt, NULL, NULL, NULL);
-	      pthread_spinlock_t lock;
-	      pthread_spin_lock(&lock);
+	      pthread_mutex_t lock;
+	      pthread_mutex_lock(&lock);
 	    ]
 	  )
 	],
diff --git a/proto/bfd/bfd.h b/proto/bfd/bfd.h
index 71f1090d..d8b5f8ea 100644
--- a/proto/bfd/bfd.h
+++ b/proto/bfd/bfd.h
@@ -82,8 +82,6 @@ struct bfd_proto
 {
   struct proto p;
 
-  pthread_spinlock_t lock;
-
   pool *tpool;
 
   struct birdloop *eloop;
-- 
2.39.5 (Apple Git-154)