[build] check for libexecinfo
[build] check for libexecinfo

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