diff --git a/libraries/liblmdb/CHANGES b/libraries/liblmdb/CHANGES
index 0d18ac1189..d924fb640c 100644
--- a/libraries/liblmdb/CHANGES
+++ b/libraries/liblmdb/CHANGES
@@ -9,6 +9,8 @@ LMDB 0.9.34 Engineering
 	ITS#10346 - fix mdb_env_copy2 with values > (2GB-16)
 	ITS#10355 - fix mplay build on musl
 	ITS#10396 - fix mdb_cursor_del0 with multiple DUPSORT cursors
+	ITS#10419 - add support for NetBSD
+	ITS#10420 - add support for Haiku
 	ITS#10421 - mdb_load: check for malicious input
 
 LMDB 0.9.33 Release (2024/05/21)
diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index a6b5375c00..1cec612013 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -135,6 +135,14 @@ typedef SSIZE_T	ssize_t;
 # endif
 #elif defined(ANDROID)
 # define MDB_FDATASYNC		fsync
+#elif defined(__HAIKU__)
+# define MDB_USE_POSIX_SEM	1
+# define MDB_FDATASYNC		fsync
+#endif
+
+/* NetBSD does not define union semun in sys/sem.h */
+#if defined(__NetBSD__) && !defined(_SEM_SEMUN_UNDEFINED)
+# define _SEM_SEMUN_UNDEFINED  1
 #endif
 
 #ifndef _WIN32