This commit updates files so that aclocal.m4 generated by aclocal(1)
works well with our configure.ac
* ac_checking.m4: merged back to configure.ac because
aclocal(1) cannot handle this macro.
* ruby_append_options.m4: no longer used.
* ruby_check_va_copy.m4: define using AC_DEFUN so that
aclocal(1) can find this macro.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62243 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
