Disable LTO and update changelog (#6777)

Author: achamayou

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres Fto [Semantic Versioning](http://semver.org/spec/v2.0.0
 
 - Joining nodes can now request a snapshot from their peers at startup, rather than relying on file access. The joinee's snapshot will be fetched and used if it is more recent than the joiner has access to. This behaviour is enabled by default, but can be disabled via the `command.join.fetch_recent_snapshot` config option (#6758).
 
+### Changed
+
+- CCF now defaults to using libstdc++ rather than libc++, and no longer builds with LTO, to improve compatibility with other C++ libraries.
+
 ## [6.0.0-dev12]
 
 [6.0.0-dev12]: https://github.com/microsoft/CCF/releases/tag/6.0.0-dev12

cmake/preproject.cmake

@@ -82,13 +82,4 @@ if("${COMPILE_TARGET}" STREQUAL "snp")
   endif()
 endif()
 
-if("${COMPILE_TARGET}" STREQUAL "snp" OR "${COMPILE_TARGET}" STREQUAL "virtual")
-  if(NOT "${CMAKE_BUILD_TYPE}" STREQUAL "Debug" AND NOT TSAN)
-    add_compile_options(-flto)
-  endif()
-  # Unconditionally make linker aware of possible LTO happening. Otherwise
-  # targets built in Debug and linked against this will fail linkage.
-  add_link_options(-flto)
-endif()
-
 set(CMAKE_CXX_STANDARD 20)