add ExtUtils::CBuilder to configure requires, and change to dynamic config
-rw-r--r-- .gitignore
-rw-r--r-- Changes
-rw-r--r-- Makefile.PL
drwxr-xr-x lib
drwxr-xr-x maint
drwxr-xr-x t
drwxr-xr-x xt