420fa0770f37619bfa29898d59dac45b6a477abb fuzz: use std::optional for sep_pos variable (Harris)
Pull request description:
This PR changes the original `size_t sep_pos` to `std::optional<size_t> sep_post_opt` to remove the warning when compiling fuzz tests.
```shell
warning: variable 'sep_pos' may be uninitialized when used here [-Wconditional-uninitialized]
```
Also, it adds `--enable-c++17` flag to CI fuzz scripts.
ACKs for top commit:
practicalswift:
ACK 420fa0770f37619bfa29898d59dac45b6a477abb
MarcoFalke:
ACK 420fa07
Tree-SHA512: e967d5d8ab8ee7394b243ff5b28bac72d30bd14774e4a206f8c87474fad22769da76e4ba4e03cbef83b8f60e5293e9d9293b613e2e2e59e187d4e59ae6b874ca
* Squashed 'src/dashbls/' content from commit 66ee820fbc
git-subtree-dir: src/dashbls
git-subtree-split: 66ee820fbc9e3b97370db8c164904af48327a124
* build: stop tracking build-system generated relic_conf.h.in
* build: add support for building bls-signatures from local subtree
* build: add exclusions to linting scripts and filters
* build: drop bls-signatures (bls-dash) from depends
Unfortunately, we need -Wno-unused-command-line-argument as configure will fail to run
with -Werror due to Dash's current build system utilizing -static-libstdc++ indiscriminately,
resulting in Clang warnings of "unused arguments".
