They use non-public functions, which is unacceptable for a public API
example. Rename the example back to avio_list_dir.
This effectively reverts c84d208c275d6a43b3c3421d38772179abf8acee and
767d780ec001167b2fd8f6cfe4ef78a3a8b1e34c.
* commit 'acb0dea27efff4b35796015b96570b59fd517078':
build: Split logic for building examples off into a separate Makefile
We already have a Makefile in doc/examples, but it's separate from the build
system and meant to be installed as part of the documentation to help users
compile the installed .c example files.
Move it to Makefile.example to make place for the new build system Makefile.
Merged-by: James Almer <jamrial@gmail.com>
