Changeset ff3f3490 in rtems for testsuites/libtests/tar01/tar01.scn

untar: Make behavior similar to GNU or BSD tar

RTEMS untar implementation had problems with overwriting or integrating
archives into existing directory structures. This patch adapts the
behavior to mimic that of a GNU tar or BSD tar and extends the tar01
test to check for the behavior. That is:

• If a directory structure exists, the files from the archive will be integrated. Existing files are overwritten.

• If a file exists and the archive contains a directory with the same name, the file is removed and a directory is created. In the above example: if l1/l2 is a file it will be overwritten with a new directory.

• If a directory exists and the archive contains a file with the same name, the directory will be replaced if it is empty. If it contains files, the result is an error.

• An archive also can contain only a file without the parent directories. If in that case one of the parent directories exists as a file extracting the archive results in an error. In the example: if l1/l2 is a file and the archive doesn't contain the directories but only the file l1/l2/x.txt that would be an error.

• In case of an error, it is possible that the archive has been partially extracted.

Closes #4552