I have this problem too, and asked about it in Modules installation path. I'm using some bash to export the variable:

function P5L {
        unset PERL5LIB;
        DIRS=(~/lang/perl/modules/{lib,share}/perl/*);
        local IFS=":";
        export PERL5LIB="${DIRS[*]}";  ## double quoted array expansio
+n indexed by "*"
} && P5L
[download]

Recently I've had to make an addition because Devel::Caller installed itself in another place: