Qt4 build fix.

src/msgpackcommon.h.in

@@ -36,8 +36,8 @@ const quint8 FIXARRAY   = 0x90;
 const quint8 FIXSTR     = 0xa0;
 const quint8 NIL        = 0xc0;
 const quint8 NEVER_USED = 0xc1;
-const quint8 FALSE      = 0xc2;
-const quint8 TRUE       = 0xc3;
+const quint8 MFALSE      = 0xc2;
+const quint8 MTRUE       = 0xc3;
 const quint8 BIN8       = 0xc4;
 const quint8 BIN16      = 0xc5;
 const quint8 BIN32      = 0xc6;