Index: /trunk/Config.kmk
===================================================================
--- /trunk/Config.kmk	(revision 66063)
+++ /trunk/Config.kmk	(revision 66064)
@@ -2810,7 +2810,9 @@
 #      -wd4242: '=' : conversion from 'uint32_t' to 'uint8_t', possible loss of data
 #      -wd4244: 'conversion' conversion from 'type1' to 'type2', possible loss of data
+#      -wd4200: nonstandard extension used : zero-sized array in struct/union
+#               Cannot generate copy-ctor or copy-assignment operator when UDT contains a zero-sized array
 VBOX_VCC_WARN_ALL ?= -W4 -Wall -wd4065 -wd4996 -wd4127 -wd4706 -wd4201 -wd4214 -wd4510 -wd4512 -wd4610 \
 	-wd4514 -wd4820 -wd4365 -wd4987 -wd4710 -wd4061 -wd4986 -wd4191 -wd4574 -wd4917 -wd4711 -wd4611 -wd4571 -wd4324 -wd4505 \
-	-wd4263 -wd4264 -wd4738
+	-wd4263 -wd4264 -wd4738 -wd4200
 #ifndef VBOX_WITH_MASOCHISTIC_WARNINGS
 # VBOX_VCC_WARN_ALL +=
Index: /trunk/include/iprt/cdefs.h
===================================================================
--- /trunk/include/iprt/cdefs.h	(revision 66063)
+++ /trunk/include/iprt/cdefs.h	(revision 66064)
@@ -2284,4 +2284,29 @@
 #define RT_ELEMENTS(aArray)                     ( sizeof(aArray) / sizeof((aArray)[0]) )
 
+/** @def RT_FLEXIBLE_ARRAY
+ * What to up inside the square brackets when declaring a structure member
+ * with a flexible size.
+ *
+ * @note    Use RT_UOFFSETOF() to calculate the structure size.
+ * @note    Never to a sizeof() on the structure or member!
+ * @note    The member must be the last one.
+ */
+#if RT_MSC_PREREQ(RT_MSC_VER_VS2010) /** @todo Probably much much earlier. */ \
+ || (defined(__cplusplus) && RT_GNUC_PREREQ(4, 1)) /** @todo Figure out when applies to the G++ compiler and -std=?? effects. */ \
+ || defined(__WATCOMC__) /* openwatcom 1.9 supports it, we don't care about older atm. */
+# define RT_FLEXIBLE_ARRAY
+# if defined(__cplusplus) && defined(_MSC_VER)
+#  pragma warning(disable:4200) /* -wd4200 does not work with VS2010 */
+# endif
+#elif defined(__STDC_VERSION__)
+# if __STDC_VERSION__ >= 1999901L
+#  define RT_FLEXIBLE_ARRAY
+# else
+#  define RT_FLEXIBLE_ARRAY                     1
+# endif
+#else
+# define RT_FLEXIBLE_ARRAY                      1
+#endif
+
 /**
  * Checks if the value is a power of two.