Merge bitcoin/bitcoin#24831: tidy: add include-what-you-use

9b0a13a289 tidy: Add include-what-you-use (fanquake)
74cd038e30 refactor: fix includes in src/init (fanquake)
c79ad935f0 refactor: fix includes in src/compat (fanquake)

Pull request description:

  We recently added a [`clang-tidy` job](https://github.com/bitcoin/bitcoin/blob/master/ci/test/00_setup_env_native_tidy.sh) to the CI, which generates a compilation database. We can leverage that now existing database to begin running [include-what-you-use](https://include-what-you-use.org/) over the codebase.

  This PR demonstrates using a mapping_file to indicate fixups / includes that may differ from IWYU suggestions. In this case, I've added some fixups for glibc includes that I've [upstreamed changes for](https://github.com/include-what-you-use/include-what-you-use/pull/1026):
  ```bash
  # Fixups / upstreamed changes
  [
    { include: [ "<bits/termios-c_lflag.h>", private, "<termios.h>", public ] },
    { include: [ "<bits/termios-struct.h>", private, "<termios.h>", public ] },
    { include: [ "<bits/termios-tcflow.h>", private, "<termios.h>", public ] },
  ]
  ```

  The include "fixing" commits of this PR:
  * Adds missing includes.
  * Swaps C headers for their C++ counterparts.
  * Removes the pointless / unmaintainable `//for abc, xyz` comments. When using IWYU, if anyone wants to see / generate those comments, to see why something is included, it is trivial to do so (IWYU outputs them by default). i.e:
  ```cpp
  // The full include-list for compat/stdin.cpp:
  #include <compat/stdin.h>
  #include <poll.h>                  // for poll, pollfd, POLLIN
  #include <termios.h>               // for tcgetattr, tcsetattr
  #include <unistd.h>                // for isatty, STDIN_FILENO
  ```

  TODO:
  - [ ] Qt mapping_file. There is one in the IWYU repo, but it's for Qt 5.11. Needs testing.
  - [ ] Boost mapping_file. There is one in the IWYU repo, but it's for Boost 1.75. Needs testing.

  I'm not suggesting we turn this on the for entire codebase, or immediately go-nuts refactoring all includes. However I think our dependency includes are now slim enough, and our CI infrastructure in place such that we can start doing this in some capacity, and just automate away include fixups / refactorings etc.

ACKs for top commit:
  MarcoFalke:
    review ACK 9b0a13a289
  jonatack:
    ACK 9b0a13a289 reviewed changes and run CI output in https://cirrus-ci.com/task/4750910332076032

Tree-SHA512: 00beab5a5f2a6fc179abf08321a15391ecccaa91ab56f3c50c511e7b29a0d7c95d8bb43eac2c31489711086f6f77319d43d803cf8ea458e7cd234a780d9ae69e

ci/test/00_setup_env_native_tidy.sh

@@ -8,7 +8,7 @@ export LC_ALL=C.UTF-8
 
 export DOCKER_NAME_TAG="ubuntu:22.04"
 export CONTAINER_NAME=ci_native_tidy
-export PACKAGES="clang llvm clang-tidy bear libevent-dev libboost-dev libminiupnpc-dev libnatpmp-dev libzmq3-dev systemtap-sdt-dev libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libqrencode-dev libsqlite3-dev libdb++-dev"
+export PACKAGES="clang libclang-dev llvm-dev clang-tidy bear cmake libevent-dev libboost-dev libminiupnpc-dev libnatpmp-dev libzmq3-dev systemtap-sdt-dev libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libqrencode-dev libsqlite3-dev libdb++-dev"
 export NO_DEPENDS=1
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false

ci/test/04_install.sh

@@ -111,6 +111,13 @@ if [[ ${USE_MEMORY_SANITIZER} == "true" ]]; then
   CI_EXEC "cd ${BASE_SCRATCH_DIR}/msan/build/ && make $MAKEJOBS cxx"
 fi
 
+if [[ "${RUN_TIDY}" == "true" ]]; then
+  CI_EXEC "mkdir -p ${BASE_SCRATCH_DIR}/iwyu/build/"
+  CI_EXEC "git clone --depth=1 https://github.com/include-what-you-use/include-what-you-use -b clang_14 ${BASE_SCRATCH_DIR}/iwyu/include-what-you-use"
+  CI_EXEC "cd ${BASE_SCRATCH_DIR}/iwyu/build && cmake -G 'Unix Makefiles' -DCMAKE_PREFIX_PATH=/usr/lib/llvm-14 ../include-what-you-use"
+  CI_EXEC "cd ${BASE_SCRATCH_DIR}/iwyu/build && make install $MAKEJOBS"
+fi
+
 if [ -z "$DANGER_RUN_CI_ON_HOST" ]; then
   echo "Create $BASE_ROOT_DIR"
   CI_EXEC rsync -a /ro_base/ "$BASE_ROOT_DIR"

ci/test/06_script_b.sh

@@ -37,6 +37,8 @@ fi
 if [ "${RUN_TIDY}" = "true" ]; then
   export P_CI_DIR="${BASE_BUILD_DIR}/bitcoin-$HOST/src/"
   CI_EXEC run-clang-tidy "${MAKEJOBS}"
+  export P_CI_DIR="${BASE_BUILD_DIR}/bitcoin-$HOST/"
+  CI_EXEC "python3 ${BASE_SCRATCH_DIR}/iwyu/include-what-you-use/iwyu_tool.py src/compat src/init -p . ${MAKEJOBS} -- -Xiwyu --cxx17ns -Xiwyu --mapping_file=${BASE_BUILD_DIR}/bitcoin-$HOST/contrib/devtools/iwyu/bitcoin.core.imp"
 fi
 
 if [ "$RUN_SECURITY_TESTS" = "true" ]; then