* tool/m4/ruby_check_va_copy.m4 (RUBY_CHECK_VA_COPY): use AC_TRY_LINK instead of AC_TRY_RUN for cross compiling. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62432 b2dd03c8-39d4-4d8f-98ff-823fe69b080e