The pcre package donwload link is broken. Quoted from the https://pcre.org/ site: "Note that the former ftp.pcre.org FTP site is no longer available. You will need to update any scripts that download PCRE source code to download via HTTPS, Git, or Subversion from the new home on GitHub instead."
Thanks for the bug report, this is already fixed on master by https://git.buildroot.net/buildroot/commit/?id=236385c50f58190f0dafb342d1d6c5115068683e