Merge remote-tracking branch 'origin/mdb.RE/0.9' into OPENLDAP_REL_ENG_2_4

libraries/liblmdb/CHANGES

 LMDB 0.9 Change Log
 
+LMDB 0.9.26 Engineering
+
 LMDB 0.9.25 Release (2020/01/30)
 	ITS#9068 fix mdb_dump/load backslashes in printable content
 	ITS#9118 add MAP_NOSYNC for FreeBSD

libraries/liblmdb/mdb.c

@@ -124,7 +124,10 @@ typedef SSIZE_T	ssize_t;
 #include <resolv.h>	/* defines BYTE_ORDER on HPUX and Solaris */
 #endif
 
-#if defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
+#if defined(__FreeBSD__) && defined(__FreeBSD_version) && __FreeBSD_version >= 1100110
+# define MDB_USE_POSIX_MUTEX	1
+# define MDB_USE_ROBUST	1
+#elif defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
 # define MDB_USE_POSIX_SEM	1
 # define MDB_FDATASYNC		fsync
 #elif defined(ANDROID)
@@ -1375,7 +1378,7 @@ static int	mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
 static int  mdb_env_read_header(MDB_env *env, MDB_meta *meta);
 static MDB_meta *mdb_env_pick_meta(const MDB_env *env);
 static int  mdb_env_write_meta(MDB_txn *txn);
-#ifdef MDB_USE_POSIX_MUTEX /* Drop unused excl arg */
+#if defined(MDB_USE_POSIX_MUTEX) && !defined(MDB_ROBUST_SUPPORTED) /* Drop unused excl arg */
 # define mdb_env_close0(env, excl) mdb_env_close1(env)
 #endif
 static void mdb_env_close0(MDB_env *env, int excl);
@@ -5133,6 +5136,17 @@ mdb_env_close0(MDB_env *env, int excl)
 				sem_unlink(env->me_txns->mti_wmname);
 			}
 		}
+#elif defined(MDB_ROBUST_SUPPORTED)
+		/* If we have the filelock:  If we are the
+		 * only remaining user, clean up robust
+		 * mutexes.
+		 */
+		if (excl == 0)
+			mdb_env_excl_lock(env, &excl);
+		if (excl > 0) {
+			pthread_mutex_destroy(env->me_txns->mti_rmutex);
+			pthread_mutex_destroy(env->me_txns->mti_wmutex);
+		}
 #endif
 		munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
 	}
@@ -6785,7 +6799,7 @@ more:
 						offset *= 4; /* space for 4 more */
 						break;
 					}
-					/* FALLTHRU: Big enough MDB_DUPFIXED sub-page */
+					/* FALLTHRU */ /* Big enough MDB_DUPFIXED sub-page */
 				case MDB_CURRENT:
 					fp->mp_flags |= P_DIRTY;
 					COPY_PGNO(fp->mp_pgno, mp->mp_pgno);