These replace our platform-specific mess in favor of c++20 endian detection
via std::endian and internal byteswap functions when necessary.
They no longer rely on autoconf detection.
Recognizing addresses from those networks allows us to accept and gossip
them, even though we don't know how to connect to them (yet).
Co-authored-by: eriknylund <erik@daychanged.com>
The way we currently test with AC_CHECK_DECLS do not work with Clang:
```bash
configure:21492: clang++-10 -std=c++11 -c -g -O2 -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS conftest.cpp >&5
conftest.cpp💯10: error: builtin functions must be directly called
(void) __builtin_clz;
^
1 error generated.
```
This also removes the __builtin_clz() check, as we don't actually use
it anywhere, and it's trvial to re-add detection if we do start using
it at some point.
All the other files in the repo which include bitcoin-config.h do so with the appropriate subfolder prefixed: config/bitcoin-config.h
The header should be included with the appropriate subfolder here as well.
This canonicalization also allows getting rid of a bit of extra configuration in Makefile.am.
- Detect endian instead of stopping configure on big-endian
- Add `byteswap.h` and `endian.h` header for compatibility with
Windows and other operating systems that don't come with them
- Update `crypto/common.h` functions to use compat
endian header
