C implementation of createrepo
run createrepo -h for usage syntax


Differences in behavior between createrepo_c and createrepo:
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>> Checksums after update

Use case:
- Repodata in repo/ are has checksum xxx
- Params: --update --checksum=yyy repo/

createrepo_c result:
- All package checksums are recalculated into yyy

original createrepo result:
- Only new and changed packages has yyy checksums
  other packages has still xxx checksums

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>> Skip symlinks param

Use case:
- Some packages in repo/ are symlinks
- Params: --skip-symlinks repo/

createrepo_c result:
- Symlinked packages are ignored

original createrepo result:
- Symlinked packages are processed
  (https://bugzilla.redhat.com/show_bug.cgi?id=828848)

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>> Base path from update-md-path repo

Use case:
- A somebody else's repo is somewhere
- The repo items have set a base path to http://foo.com/
- We want to create metadata for our repo
- Some packages in our repo are same as packages in somebody else's repo
- We want to speed up creation of our repodata with
  combo --update and --update-md-path=somebody_else's_repo
- Params: --update --update-md-path=ftp://somebody.else/repo our_repo/

createrepo_c results:
- All our packages have no base path set (if we don't set --baseurl explicitly)

original createrepo result:
- Some packages in metadata (which was same in our repo and in somebody
  else's repo) have base path set to http://foo.com/i

-----------------------------------------------

>> Crippled paths in filelists.xml after update

Use case:
- A repo with old metadata exists
- We want to update metadata
- Params: --update repo/

createrepo_c results:
- All is fine

original createrepo result:
- Some paths in filelists.xml are crippled
  (https://bugzilla.redhat.com/show_bug.cgi?id=835565)

-----------------------------------------------

>> --update leaves behind some old repodata files

Use case:
- A repo with repodata created with --simple-md-filenames exists
- We want to update repodata to have checksums in filenames
- Params: --update repo/

createrepo_c results:
- All repodata contains checksum in the name

original createrepo result:
- All repodata contains checksum in the name
- There are old metadata without checksum in the name too
- (https://bugzilla.redhat.com/show_bug.cgi?id=836917)

