mkmf.rb: prefer $LIBPATH than $DEFLIBPATH
$LIBPATH
$DEFLIBPATH
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
mkmf.rb: prefer $LIBPATH than $DEFLIBPATH
user specified
$LIBPATH
than$DEFLIBPATH
. [ruby-core:62100][ruby-trunk - Bug #9760]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e