When assigning a name to the sdbfs struct, it's usual to use a static
string. Unfortunately, this generates warnings about discarded
qualifiers. We can fix that issue by making the struct member a const
char pointer.

Use a platform independent macro to determine the parameter format
specifier.

Commit taken from [1].

[1] https://github.com/lnls-dig/halcs/commit/096423678988634421701a54d94963fabc12ff76

Fix warnings by changing values into unsigned ones. Based on commit
from [1], but doing it more correctly:

- use size_t for comparisons with sizeof
- convert offset to unsigned long (type of fs->f_len) so count is
  automatically promoted as well and there's no chance for overflow

[1] https://github.com/lnls-dig/halcs/commit/b1f537ee95297a114dd72da57585bb5ed55a8a08

Also removes any overflow danger by using the correct data type.

Commit taken from [1].

[1] https://github.com/lnls-dig/halcs/commit/b6b3e031597dc04528df8ede642e1b16803e7594

Commit taken from [1].

[1] https://github.com/lnls-dig/halcs/commit/2d4b7670c46b684fec8348bfb59b39723335a260

Commit taken from [1].

[1] https://github.com/lnls-dig/halcs/commit/d409d183ba4b4c49a4b8be0ab6900e01e8f73390

Commit taken from [1].

[1] https://github.com/lnls-dig/halcs/commit/609ad2b99733c5ecdea440b631531e45f3d821d2

Commit taken from [1].

[1] wrpc-sw@bcb4fdef

In sdbfs_fwrite(), memcpy should copy data from buf to file.

Commit taken from [1].

[1] wrpc-sw@3aebf265

sdbfs: relicense lib to LGPL v2.1

See merge request !1

The userspace and kernel binaries are kept as GPL v2 but the library has
been relicensed as LGPL v2.1 in order to allow it to be linked to
proprietary software.

The permission to relicense the files has been approved by CERN in 2018
and then in 2021 (and also by its main author).

This avoids sleeping in interrupt handlers.