diff --git a/vendors/ocaml-lmdb/src/lmdb.h b/vendors/ocaml-lmdb/src/lmdb.h
index 0a10fc92c..16c574a4d 100644
--- a/vendors/ocaml-lmdb/src/lmdb.h
+++ b/vendors/ocaml-lmdb/src/lmdb.h
@@ -136,7 +136,7 @@
  *
  *	@author	Howard Chu, Symas Corporation.
  *
- *	@copyright Copyright 2011-2017 Howard Chu, Symas Corp. All rights reserved.
+ *	@copyright Copyright 2011-2018 Howard Chu, Symas Corp. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted only as authorized by the OpenLDAP
diff --git a/vendors/ocaml-lmdb/src/mdb.c b/vendors/ocaml-lmdb/src/mdb.c
index f5f99a590..a487e156f 100644
--- a/vendors/ocaml-lmdb/src/mdb.c
+++ b/vendors/ocaml-lmdb/src/mdb.c
@@ -5,7 +5,7 @@
  *	BerkeleyDB API, but much simplified.
  */
 /*
- * Copyright 2011-2017 Howard Chu, Symas Corp.
+ * Copyright 2011-2018 Howard Chu, Symas Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,29 +48,35 @@
  * the full size. These APIs are defined in <wdm.h> and <ntifs.h>
  * but those headers are meant for driver-level development and
  * conflict with the regular user-level headers, so we explicitly
- * declare them here. Using these APIs also means we must link to
- * ntdll.dll, which is not linked by default in user code.
+ * declare them here. We get pointers to these functions from
+ * NTDLL.DLL at runtime, to avoid buildtime dependencies on any
+ * NTDLL import libraries.
  */
-NTSTATUS WINAPI
-NtCreateSection(OUT PHANDLE sh, IN ACCESS_MASK acc,
+typedef NTSTATUS WINAPI (NtCreateSectionFunc)
+  (OUT PHANDLE sh, IN ACCESS_MASK acc,
   IN void * oa OPTIONAL,
   IN PLARGE_INTEGER ms OPTIONAL,
   IN ULONG pp, IN ULONG aa, IN HANDLE fh OPTIONAL);
 
+static NtCreateSectionFunc *NtCreateSection;
+
 typedef enum _SECTION_INHERIT {
 	ViewShare = 1,
 	ViewUnmap = 2
 } SECTION_INHERIT;
 
-NTSTATUS WINAPI
-NtMapViewOfSection(IN PHANDLE sh, IN HANDLE ph,
+typedef NTSTATUS WINAPI (NtMapViewOfSectionFunc)
+  (IN PHANDLE sh, IN HANDLE ph,
   IN OUT PVOID *addr, IN ULONG_PTR zbits,
   IN SIZE_T cs, IN OUT PLARGE_INTEGER off OPTIONAL,
   IN OUT PSIZE_T vs, IN SECTION_INHERIT ih,
   IN ULONG at, IN ULONG pp);
 
-NTSTATUS WINAPI
-NtClose(HANDLE h);
+static NtMapViewOfSectionFunc *NtMapViewOfSection;
+
+typedef NTSTATUS WINAPI (NtCloseFunc)(HANDLE h);
+
+static NtCloseFunc *NtClose;
 
 /** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it
  *  as int64 which is wrong. MSVC doesn't define it at all, so just
@@ -4690,6 +4696,21 @@ mdb_env_open2(MDB_env *env, int prev)
 		env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
 	else
 		env->me_pidquery = PROCESS_QUERY_INFORMATION;
+	/* Grab functions we need from NTDLL */
+	if (!NtCreateSection) {
+		HMODULE h = GetModuleHandle("NTDLL.DLL");
+		if (!h)
+			return MDB_PROBLEM;
+		NtClose = (NtCloseFunc *)GetProcAddress(h, "NtClose");
+		if (!NtClose)
+			return MDB_PROBLEM;
+		NtMapViewOfSection = (NtMapViewOfSectionFunc *)GetProcAddress(h, "NtMapViewOfSection");
+		if (!NtMapViewOfSection)
+			return MDB_PROBLEM;
+		NtCreateSection = (NtCreateSectionFunc *)GetProcAddress(h, "NtCreateSection");
+		if (!NtCreateSection)
+			return MDB_PROBLEM;
+	}
 #endif /* _WIN32 */
 
 #ifdef BROKEN_FDATASYNC
@@ -5553,7 +5574,7 @@ mdb_env_close0(MDB_env *env, int excl)
 	if (env->me_fd != INVALID_HANDLE_VALUE)
 		(void) close(env->me_fd);
 	if (env->me_txns) {
-		MDB_PID_T pid = env->me_pid;
+		MDB_PID_T pid = getpid();
 		/* Clearing readers is done in this function because
 		 * me_txkey with its destructor must be disabled first.
 		 *
@@ -7648,8 +7669,9 @@ prep_subDB:
 				} else {
 					memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
 						olddata.mv_size - fp->mp_upper - PAGEBASE);
+					memcpy((char *)(&mp->mp_ptrs), (char *)(&fp->mp_ptrs), NUMKEYS(fp) * sizeof(mp->mp_ptrs[0]));
 					for (i=0; i<NUMKEYS(fp); i++)
-						mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
+						mp->mp_ptrs[i] += offset;
 				}
 			}
 
diff --git a/vendors/ocaml-lmdb/src/midl.c b/vendors/ocaml-lmdb/src/midl.c
index 499df17cc..341021cc5 100644
--- a/vendors/ocaml-lmdb/src/midl.c
+++ b/vendors/ocaml-lmdb/src/midl.c
@@ -3,8 +3,8 @@
 /* $OpenLDAP$ */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 2000-2016 The OpenLDAP Foundation.
- * Portions Copyright 2001-2017 Howard Chu, Symas Corp.
+ * Copyright 2000-2018 The OpenLDAP Foundation.
+ * Portions Copyright 2001-2018 Howard Chu, Symas Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
diff --git a/vendors/ocaml-lmdb/src/midl.h b/vendors/ocaml-lmdb/src/midl.h
index 39a87b52c..a0d5727cf 100644
--- a/vendors/ocaml-lmdb/src/midl.h
+++ b/vendors/ocaml-lmdb/src/midl.h
@@ -11,8 +11,8 @@
 /* $OpenLDAP$ */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 2000-2016 The OpenLDAP Foundation.
- * Portions Copyright 2001-2017 Howard Chu, Symas Corp.
+ * Copyright 2000-2018 The OpenLDAP Foundation.
+ * Portions Copyright 2001-2018 Howard Chu, Symas Corp.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without