Path::Tiny loads slower than other modules

[scottchiefbaker]

Using perl-module-startup-time.pl I'm able to calculate the startup time for Path::Tiny (no methods called, just loading the module) at 15.8ms. As a comparison here are some other modules on the same system.

   File::Basename adds  3.1 ms to startup time
      Time::HiRes adds  1.5 ms to startup time
   Getopt::Long adds    9.9 ms to startup time
     Data::Dumper adds  8.9 ms to startup time

That majority of the startup time in Path::Tiny is spent loading Carp and File::Spec. File::Spec is only used in rootdir(). Changing these two modules to load on-demand drops the startup time to 10.4ms. This is a ~34% improvement in startup time.

Before I go to the trouble of writing up a full PR is this something you'd consider accepting? Attached is a rough patch of the concept.

path-tiny-lazy-load.patch.gz