The entire file scope suppression check was checking for the rule item
list to be None instead of looking for None as an entry into the list.

Correct this check and modify the documentation to explicitly state that
an entry of None in the rule item list will set the scope for that
suppression to be the entire file.

To run:

../../cppcheck --suppressions-list=suppressions.txt --dump misra-suppressions*-test.c
python ../misra.py misra-suppressions*-test.c.dump

There should be no violations reported

For environments that run cppcheck from the build system cppcheck may be
passed a filename that is a complete path.

Often this path will include a portion that is specific to the developer
or to the environment where the project is located.

The per-file suppression rules do filename matching based on the
filename passed to cppcheck. To match any path information also has to
be included into the suppressions file provided to cppcheck via the
--suppressions-list= option.

This limits the usefulness of the per-file based suppressions because
it requires the suppression to be customized on a per instance basis.

Add a option "--file-prefix" that allows a prefix to be excluded from
the file path when doing the suppression filename matching.

Example.

Given the following structure:

/test/path1/misra-suppressions1-test.c
/test/path1/misra-suppressions2-test.c

specifying --file-prefix /test/path1 will allow the use of
misra-suppressions1-test.c and misra-suppressions2-test.c as filenames
in the suppressions file without leading patch information but still
match the suppression rule.

To run:

../../cppcheck --suppressions-list=suppressions.txt \
    --dump misra-suppressions*-test.c \
           path1/misra-suppressions*-test.c

python ../misra.py misra-suppressions*-test.c.dump \
                   path1/misra-suppressions*-test.c

There should be no violations reported