diff --git a/include/boost/mpl/string.hpp b/include/boost/mpl/string.hpp
index 345918f..e789856 100644
--- a/include/boost/mpl/string.hpp
+++ b/include/boost/mpl/string.hpp
@@ -59,7 +59,7 @@ namespace boost { namespace mpl
     #define BOOST_MPL_MULTICHAR_LENGTH(c)                                                           \
       (std::size_t)((c<CHAR_MIN) ? 4 : ((c>0xffffff)+(c>0xffff)+(c>0xff)+1))
 
-    #if defined(BOOST_ENDIAN_LITTLE_BYTE) && defined(__SUNPRO_CC)
+    #if BOOST_ENDIAN_LITTLE_BYTE && defined(__SUNPRO_CC)
 
         #define BOOST_MPL_MULTICHAR_AT(c,i)                                                         \
           (char)(0xff&((unsigned)(c)>>(8*(std::size_t)(i))))