Use of uninitialized value $vals in index at /usr/local/share/perl5/HTTP/Headers.pm line 277.
Use of uninitialized value $vals in concatenation (.) or string at /usr/local/share/perl5/HTTP/Headers.pm line 280.
I don't know when or why it started, but I've tried all of:
/usr/local/share/perl5/HTTP/Headers.pm:our $VERSION = "6.10";
This is on a CentOS machine, not a Mac, in case that matters.