Merge pull request littlefs-project#263 from rojer/wundef

Fix build with -Wundef

Bump version to v2.1

Fixed 32-bit/64-bit Ubuntu multilib issue in Travis

Fixed limit of inline files based on LFS_ATTR_MAX

The maximum limit of inline files and attributes are unrelated, but were
not at a point in littlefs v2 development. This should be checking
against the bit-field limit in the littlefs tag.

Found by lsilvaalmeida

Fixed migration test condition for prefix branches

Both the littlefs-fuse and littlefs-migration test jobs depend on
the external littlefs-fuse repo. But unfortunately, the automatic
patching to update the external repo with the version under test
does not work with the prefix branches.

In this case we can just skip these tests, they've already been tested
multiple times to get to this point.

Fixed buffer overflow due to mistaking prog_size for cache_size

found by ajaybhargav

Merge pull request littlefs-project#151 from Krakonos/master

Fixed documentation for return lfs_dir_read return value.

Merge pull request littlefs-project#85 from ARMmbed/v2-alpha

v2: Metadata logging, custom attributes, inline files, and a major version bump

Added automatic version prefixing to releases

The script itself is a part of .travis.yml, using ./scripts/prefix.py
for applying prefixes to the source code.

This purpose of the automatic job is to provide a branch containing
version prefixes, to avoid name conflicts in binaries containing
different major versions of littlefs with only a git clone.

As a part of each release, two branches and a tag are created:
- vN        - moving branch
- vN-prefix - moving branch
- vN.N.N    - immutable tag

The major version branch (vM) is created on major releases, but updated
every patch release. The patch version tag (vM.M.P) is created every
patch release. Patch releases occur every time a commit is merged into
master, though multiple merges may be coalesced.

The major prefix branch (vM-prefix) is modified with the ./scripts/prefix.py
script. Note that this branch is updated as a synthetic merge commit
with the previous history of vM-prefix. The reason for this is to allow
users to easily update vM-prefix with a `git pull` as they would for
other branches.

A---B---C---D---E master, v1, v1.7.3
     \       \   \
      F-------G---H v1-prefix

Merge pull request littlefs-project#135 from johnlunney/patch-1

Add missing word (and reflow text)