diff --git a/lauxlib.c b/lauxlib.c
index 7b14ca4d..2d16c9ce 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.c,v 1.288 2016/12/04 20:17:24 roberto Exp roberto $
+** $Id: lauxlib.c,v 1.289 2016/12/20 18:37:00 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -496,7 +496,7 @@ static void *newbox (lua_State *L, size_t newsize) {
 ** check whether buffer is using a userdata on the stack as a temporary
 ** buffer
 */
-#define buffonstack(B)	((B)->b != (B)->initb)
+#define buffonstack(B)	((B)->b != (B)->init.b)
 
 
 /*
@@ -568,7 +568,7 @@ LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
 
 LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
   B->L = L;
-  B->b = B->initb;
+  B->b = B->init.b;
   B->n = 0;
   B->size = LUAL_BUFFERSIZE;
 }
diff --git a/lauxlib.h b/lauxlib.h
index 1d65c975..8de19916 100644
--- a/lauxlib.h
+++ b/lauxlib.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.h,v 1.130 2016/12/04 20:17:24 roberto Exp roberto $
+** $Id: lauxlib.h,v 1.131 2016/12/06 14:54:31 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -150,7 +150,10 @@ typedef struct luaL_Buffer {
   size_t size;  /* buffer size */
   size_t n;  /* number of characters in buffer */
   lua_State *L;
-  char initb[LUAL_BUFFERSIZE];  /* initial buffer */
+  union {
+    LUAI_MAXALIGN;  /* ensure maximum alignment for buffer */
+    char b[LUAL_BUFFERSIZE];  /* initial buffer */
+  } init;
 } luaL_Buffer;
 
 
diff --git a/llimits.h b/llimits.h
index fa14dfc7..14940550 100644
--- a/llimits.h
+++ b/llimits.h
@@ -1,5 +1,5 @@
 /*
-** $Id: llimits.h,v 1.140 2015/10/21 18:40:47 roberto Exp roberto $
+** $Id: llimits.h,v 1.141 2015/11/19 19:16:22 roberto Exp roberto $
 ** Limits, basic types, and some other 'installation-dependent' definitions
 ** See Copyright Notice in lua.h
 */
@@ -60,21 +60,6 @@ typedef unsigned char lu_byte;
 
 
 
-/* type to ensure maximum alignment */
-#if defined(LUAI_USER_ALIGNMENT_T)
-typedef LUAI_USER_ALIGNMENT_T L_Umaxalign;
-#else
-typedef union {
-  lua_Number n;
-  double u;
-  void *s;
-  lua_Integer i;
-  long l;
-} L_Umaxalign;
-#endif
-
-
-
 /* types of 'usual argument conversions' for lua_Number and lua_Integer */
 typedef LUAI_UACNUMBER l_uacNumber;
 typedef LUAI_UACINT l_uacInt;
diff --git a/lobject.h b/lobject.h
index 7c521ba2..c8f9adb3 100644
--- a/lobject.h
+++ b/lobject.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.h,v 2.117 2016/08/01 19:51:24 roberto Exp roberto $
+** $Id: lobject.h,v 2.118 2017/04/11 18:41:09 roberto Exp roberto $
 ** Type definitions for Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -317,7 +317,7 @@ typedef struct TString {
 ** Ensures that address after this type is always fully aligned.
 */
 typedef union UTString {
-  L_Umaxalign dummy;  /* ensures maximum alignment for strings */
+  LUAI_MAXALIGN;  /* ensures maximum alignment for strings */
   TString tsv;
 } UTString;
 
@@ -357,7 +357,7 @@ typedef struct Udata {
 ** Ensures that address after this type is always fully aligned.
 */
 typedef union UUdata {
-  L_Umaxalign dummy;  /* ensures maximum alignment for 'local' udata */
+  LUAI_MAXALIGN;  /* ensures maximum alignment for 'local' udata */
   Udata uv;
 } UUdata;
 
diff --git a/ltests.c b/ltests.c
index 77f0163d..4ac2c702 100644
--- a/ltests.c
+++ b/ltests.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 2.214 2017/04/19 18:46:47 roberto Exp roberto $
+** $Id: ltests.c,v 2.215 2017/04/24 16:59:26 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -81,7 +81,7 @@ static int tpanic (lua_State *L) {
 #define MARK		0x55  /* 01010101 (a nice pattern) */
 
 typedef union Header {
-  L_Umaxalign a;  /* ensures maximum alignment for Header */
+  LUAI_MAXALIGN;
   struct {
     size_t size;
     int type;
diff --git a/luaconf.h b/luaconf.h
index 33ff3604..f7ac7160 100644
--- a/luaconf.h
+++ b/luaconf.h
@@ -1,5 +1,5 @@
 /*
-** $Id: luaconf.h,v 1.259 2016/12/22 13:08:50 roberto Exp roberto $
+** $Id: luaconf.h,v 1.260 2017/04/19 16:34:35 roberto Exp roberto $
 ** Configuration file for Lua
 ** See Copyright Notice in lua.h
 */
@@ -761,6 +761,12 @@
 #define LUAL_BUFFERSIZE   ((int)(0x80 * sizeof(void*) * sizeof(lua_Integer)))
 #endif
 
+/*
+@@ LUAI_MAXALIGN defines fields that, when used in a union, ensure
+** "maximum" alignment for the other items in that union.
+*/
+#define LUAI_MAXALIGN  lua_Number n; double u; void *s; lua_Integer i; long l
+
 /* }================================================================== */