ruby/ruby.h: rb_block_call_func_t

* include/ruby/ruby.h (rb_block_call_func_t): strict check for
  rb_block_call_func* if RB_BLOCK_CALL_FUNC_STRICT is set.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e