First thx for these very useful lib!
I encountered some issues when linking with `libcpptrace`. Typically,
here is the error I got:
```
/usr/bin/ld: lib/cpptrace/lib/libcpptrace.a(cpptrace.cpp.o): relocation R_X86_64_32S against symbol `_ZTVNSt7__cxx1115basic_stringbufIcSt11char_traitsIcESaIcEEE@@GLIBCXX_3.4.21' can not be used when making a PIE object; recompile with -fPIE
```
I just added the `POSITION_INDEPENDENT_CODE ON` flag on the targets, and
now it works like a charm :-).
This is (perhaps) mainly for discussion as I saw you removed
`clang-tidy` checks last year. These fix a variety of minor things.
With one of the options that I was using, these still remain:
```
/Users/bruce/Development/custodian/cpptrace/src/symbols/../utils/utils.hpp:235:22: warning: noexcept specifier on the move constructor evaluates to 'false' [performance-noexcept-move-constructor]
235 | noexcept(std::is_nothrow_move_constructible<T>::value)
| ^
/Users/bruce/Development/custodian/cpptrace/src/symbols/../utils/utils.hpp:250:64: warning: noexcept specifier on the move assignment operator evaluates to 'false' [performance-noexcept-move-constructor]
250 | noexcept(std::is_nothrow_move_assignable<T>::value && std::is_nothrow_move_constructible<T>::value)
| ^
```
This is set by the build system when it is available and not set when
not available (and not set to 1/0 respectively).
The current code can generate a warning when this preprocessor
definition is not defined.
When building with Clang installed with Homebrew:
```
-- The C compiler identification is Clang 17.0.6
-- The CXX compiler identification is Clang 17.0.6
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /opt/homebrew/opt/llvm/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/homebrew/opt/llvm/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
```
I get the following error:
```
/opt/homebrew/opt/llvm/bin/llvm-ranlib: error: Invalid option: '-no_warning_for_no_symbols'
make[2]: *** [_deps/zstd-build/lib/libzstd.a] Error 1
make[2]: *** Deleting file `_deps/zstd-build/lib/libzstd.a'
make[1]: *** [_deps/zstd-build/lib/CMakeFiles/libzstd_static.dir/all] Error 2
make: *** [all] Error 2
```
If I instead build with AppleClang:
```
-- The C compiler identification is AppleClang 15.0.0.15000100
-- The CXX compiler identification is AppleClang 15.0.0.15000100
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
```
It works as expected.
Source of the problem is found at `CMakeLists.txt:282`:
```CMake
if(APPLE)
SET(CMAKE_C_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
SET(CMAKE_CXX_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
endif()
```
Changing it to check specifically for AppleClang appears to fix the
problem for me:
```CMake
if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
SET(CMAKE_C_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
SET(CMAKE_CXX_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
endif()
```
This pull request includes a minor change to the `README.md` file. The
change updates the link to the `signal-safe-tracing.md` file, moving it
into the `docs` directory.
