[build] forgot how local::lib works

Should be -Mlib=local/lib/perl5 not -Mlib=local.  The --local-lib
option makes a full /usr/local like tree.

    ./local
    ├── bin
    ├── lib
    │   └── perl5
    │       └── x86_64-linux
    └── man
        ├── man1
        └── man3

149 directories