FlatCC FlatBuffers in C for C Files

Release 0.6.4 fixes a few unlikely vulnerabilities (adversial schema in flatcc parser), a memory leak on builder reuse, and a failure to allow a retry after an allocation error in low memory. Some were reported as CVEs through apparent AI assisted issue reporting, despite low practical impact, hence this release.

CHANGELOG for 0.6.4

[0.6.4]

• Fix buffer overruns in lexer when adversarial schema presented to parser (#384, [#385]).
• Avoid operating on undefined parser state after detecting errors (duplicate symbol, recursive structs) (#387, [#388]).
• Clear hash table memory to prevent memory leak when clearing parser (#389).
• Gracefully handle allocation error in runtime hashtable (#393).
• Silence Visual Studio unsigned negation warnings in pprintint.h via pwarnings.h.