Documented specific checks/subchecks for header file verification
Simplified the process, now we use simple regex to remove macros from
the current header. Before, we re-ran preprocess_one_header()
function with removed `#include ...`s from the header under test, so
we were looking into the actual header (rather than included headers)
when checking for `extern "C"` keyword.
The procedure is easier to follow without this recursion (mostly because
in the second execution we might encounter compilation failers and
ignore them).
Note that this procedure is not 100% correct (we might see some false
positive and false negatives)
When a public header contains _Static_assert or static_assert, check_public_headers.py script will detect it and report it as an issue.
Indeed, public headers shall now use ESP_STATIC_ASSERT.
check_public_headers.py would fail when reading non-ascii chars on systems where
the default encoding was ascii.
Also fixes error handling issues, as any uncaught exeception would cause the program
to run indefinitely.
Also added a command line option to reduce the analysis to a specific
directory only. This is useful for local execution for checking updated
headers with verbose flag set.
Additional test compiling the header to produce assembly:
- checks if header really compiles (previously validated only by
preprocessor)
- checks that the header produced empty object, no inline code to be
present in public headers
Closes IDF-1324
