merge revision(s) 54716,54719,54750: [Backport #12314]
* configure.in: don't use the system-provided round(3) on AIX. In AIX, round(0.49999999999999994) returns 1.0. Use round() in numeric.c instead. * configure.in: add missing -lm for AIX.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@54771 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 54716,54719,54750: [Backport #12314]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@54771 b2dd03c8-39d4-4d8f-98ff-823fe69b080e