Update to upstream version '4.3.1'
with Debian dir 908f68ae7eff4a83ff23569399d901dbee7a9828

Update to upstream version '4.3.0'
with Debian dir 875062c0e9de0e6a16f9da5fbc7206ea34511f4f

bzrtp 1.0.6 FTBFSes with GCC-8 due to

	error: cast between incompatible function types

upstream currently works around this by setting the same with Pragmas, see
https://gitlab.linphone.org/BC/public/bzrtp/commit/e86b99fdc51c95f4d4997d7fdcfdfe0d1589ca92?w=1.
Unfortunately they have added a lot of whitespace noise in the same commit
and even without them the patch doesn't apply cleanly.

Append -Wno-cast-function-type to CFLAGS for now until upstream has fixed
the code.

Closes: #897714

Upstream version 1.0.6

Suppress arguably bogus lintian warning about shared license not written verbatim but instead referenced in machine-readable form (see bug#786450).