remove BOOST_NOINLINE fallback

Author: grisumbras

include/boost/json/detail/config.hpp

@@ -48,16 +48,6 @@
 # endif
 #endif
 
-#ifndef BOOST_NOINLINE
-# ifdef _MSC_VER
-#  define BOOST_NOINLINE __declspec(noinline)
-# elif defined(__GNUC__) || defined(__clang__)
-#  define BOOST_NOINLINE __attribute__((noinline))
-# else
-#  define BOOST_NOINLINE
-# endif
-#endif
-
 #ifndef BOOST_THROW_EXCEPTION
 # ifndef BOOST_NO_EXCEPTIONS
 #  define BOOST_THROW_EXCEPTION(x) throw(x)