* include/ruby/missing.h (explicit_bzero_by_memset_s): remove
  inline implementation by memset_s, which needs a macro before
  including headers and can cause problems in extension libraries
  by the order of the macro and headers.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53493 b2dd03c8-39d4-4d8f-98ff-823fe69b080e