Fixed compiler warnings (for linux and win32 and win64)

Fixed a couple of usage of not initialized warnings (unlikely cases)

include/my_global.h

@@ -846,6 +846,21 @@ typedef long long	my_ptrdiff_t;
 #define ADD_TO_PTR(ptr,size,type) (type) ((byte*) (ptr)+size)
 #define PTR_BYTE_DIFF(A,B) (my_ptrdiff_t) ((byte*) (A) - (byte*) (B))
 
+/*
+  Custom version of standard offsetof() macro which can be used to get
+  offsets of members in class for non-POD types (according to the current
+  version of C++ standard offsetof() macro can't be used in such cases and
+  attempt to do so causes warnings to be emitted, OTOH in many cases it is
+  still OK to assume that all instances of the class has the same offsets
+  for the same members).
+
+  This is temporary solution which should be removed once File_parser class
+  and related routines are refactored.
+*/
+
+#define my_offsetof(TYPE, MEMBER) \
+        ((size_t)((char *)&(((TYPE *)0x10)->MEMBER) - (char*)0x10))
+
 #define NullS		(char *) 0
 /* Nowdays we do not support MessyDos */
 #ifndef NEAR