skip when loaded twice, but don't throw
skip when loaded twice, but don't throw

GerHobbelt/xregexp,slevithan/xregexp,GerHobbelt/xregexp,slevithan/XRegExp,vsimonian/xregexp,imvijaybala/xregexp,Iced-Tea/xregexp,sagarrakshe/xregexp,carabina/xregexp,slevithan/xregexp,imvijaybala/xregexp,kod3r/xregexp,exexzian/xregexp,slevithan/xregexp,cesarmarinhorj/xregexp,GerHobbelt/xregexp,Akylas/xregexp,carabina/xregexp,sagarrakshe/xregexp,mathiasbynens/xregexp,Iced-Tea/xregexp,BeardandFedora/xregexp,cesarmarinhorj/xregexp,mathiasbynens/xregexp,vsimonian/xregexp,kod3r/xregexp,mathiasbynens/xregexp,Akylas/xregexp,exexzian/xregexp,mathiasbynens/xregexp,slevithan/XRegExp