[build] use isdigit
[build] use isdigit

sureshsundriyal/lnav,tstack/lnav,acleasby/lnav,tstack/lnav,sureshsundriyal/lnav,tstack/lnav,tstack/lnav,acleasby/lnav,acleasby/lnav,sureshsundriyal/lnav,sureshsundriyal/lnav,acleasby/lnav,acleasby/lnav