Merge changes I3ccf85d5,I731adcff,I6f5f9cec,I9f773287,Iabf796dc, ...

* changes:
  Update gitignore for Cargo.lock and tags
  Use local rules for flex/bison
  Specify bt_shim_ffi dependency to bluetoothtbd
  Fix rust build in build.py
  Avoid const value_type of vector
  Guard printing PKG_CONFIG_PATH in build.py
  Add missing #include <string.h> for memcpy
  Fix packetgen outputs