9c96f1008b tidy: enable modernize-use-nullptr (fanquake)
e53274868e Don't use zero as null pointer constant (-Wzero-as-null-pointer-constant) (practicalswift)
Pull request description:
Alternative to #15112 which uses `clang-tidy` to do perform the checking, rather than `-Wzero-as-null-pointer-constant`, and avoids having to uses pragmas, i.e:
```cpp
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#if defined(HAVE_W_ZERO_AS_NULL_POINTER_CONSTANT)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
#pragma GCC diagnostic ignored "-Wunknown-pragmas"
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
#endif
```
to suppress warnings coming from upstream code.
Can be tested by dropping the preceding commit. Should produce errors like:
```bash
clang-tidy-14 --use-color -p=/home/ubuntu/ci_scratch/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu /home/ubuntu/ci_scratch/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/netbase.cpp
/home/ubuntu/ci_scratch/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/netbase.cpp:678:36: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
if (!Socks5(strDest, port, 0, sock)) {
^
nullptr
```
ACKs for top commit:
laanwj:
Concept and code review ACK 9c96f1008b
Tree-SHA512: d822a354e44ba8f7fc53da9a4be7de5c25cc4ffc7c57651b76fdd1a030764b0390cfd79fca94685b8a3ff4f4d13054764f12d1f0d8c2a1b9ba519a7524f7f5bf
cc3877f831