Added (for compiler versions that support it):
-Wmissing-declarations
-Wzero-as-null-pointer-constant
Then, fixes to problems identified by the extra warnings
Tested only on GCC 9.4.0
Adjusted the CPP code generator to output nullptr where appropriate,
to satisfy -Wzero-as-null-pointer-constant
Added a lot of 'static' declarations in front of functions,
to satisfy -Wmissing-declarations,
and wrap static function defs in anonymous namespaces.
There are advantages to both anonymous namespaces and static,
it seems that marking a function as static will not publish the name in
the symbol table at all, thus giving the linker less work to do.
Having a static_assert on MSAN and ASAN prevents
the fuzzers from being used with different engines,
like TSAN, UBSAN, … but also with fuzzers that aren't
using MSAN/ASAN like afl for example.
* Make the Parser independent from the global C-locale
* Set a specific test locale using the environment variable FLATBUFFERS_TEST_LOCALE
* Remove redundant static qualifiers
Paul Harris