Clean up CI, CMake, Makefile, and Bazel files

- CMakeLists.txt: avoid VERSION_GREATER_EQUAL, which CMake < 3.7 lacks
- ci.cmake: test JSON_DisableTupleReferenceConversion in ci_cmake_flags,
  remove unused variables and unreachable per-compiler targets, look up
  Clang tools consistently, forward CMAKE_CXX_FLAGS to ci_module_cpp20,
  format json_literals.hpp and remove backups in ci_test_amalgamation
- BUILD.bazel: add json_literals.hpp to the single-header target
- workflows: format json_literals.hpp before copying it, drop the obsolete
  natvis --version plumbing, name natvis and macro_builder in failure
  messages, drop the duplicate amalgamation job, install Valgrind only
  where needed, republish docs on version bumps, fix stale names
- Makefile: complete .PHONY and help, check-amalgamation always restores
  the checked-in files, natvis uses its own venv, macro_builder_check
  installs astyle, clean removes the fuzzer binaries
- remove tools/amalgamate/config_json_view.json (json_view.hpp is not on
  develop yet)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/check_amalgamation.yml

@@ -83,8 +83,7 @@ jobs:
           # byte for byte), so there is nothing to gain from checking out a
           # separate copy, and doing so would make this step fail on a PR
           # that adds support for a new dispatch table until that PR itself
-          # merges to develop, the same way generate_natvis.py's --version
-          # requirement briefly did.
+          # merges to develop.
           TMPDIR=$(mktemp -d ./macro_builder_check.XXXXXX)
           c++ -std=c++11 tools/macro_builder/main.cpp -o "$TMPDIR/macro_builder"
           "$TMPDIR/macro_builder" > "$TMPDIR/paste.hpp"
@@ -117,7 +116,6 @@ jobs:
 
           python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json.json -s .
           python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json_fwd.json -s .
-          cp include/nlohmann/json_literals.hpp $INCLUDE_DIR/json_literals.hpp
 
           # the header list of the Bazel "json" target must match the files in include/
           cmake -P cmake/scripts/gen_bazel_build_file.cmake
@@ -138,17 +136,13 @@ jobs:
           ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
             $(find $SOURCE_DIRS -type f \( -name '*.hpp' -o -name '*.cpp' -o -name '*.cu' \) -not -path 'tests/thirdparty/*' -not -path 'tests/abi/include/nlohmann/*' | sort)
 
+          # json_literals.hpp is copied verbatim from the (now formatted) include/
+          # directory, like `make amalgamate` does
+          cp include/nlohmann/json_literals.hpp $INCLUDE_DIR/json_literals.hpp
+
       - name: Regenerate nlohmann_json.natvis
         run: |
           cd $MAIN_DIR
-          # Pass --version explicitly so this step also works with the tool
-          # copy from develop before this repository's own generate_natvis.py
-          # learns to derive the version itself: the older script requires
-          # --version, and the newer one accepts it as an explicit override.
-          ABI_MACROS=include/nlohmann/detail/abi_macros.hpp
-          VERSION_MAJOR=$(grep -m1 'define NLOHMANN_JSON_VERSION_MAJOR' $ABI_MACROS | grep -o '[0-9]\+')
-          VERSION_MINOR=$(grep -m1 'define NLOHMANN_JSON_VERSION_MINOR' $ABI_MACROS | grep -o '[0-9]\+')
-          VERSION_PATCH=$(grep -m1 'define NLOHMANN_JSON_VERSION_PATCH' $ABI_MACROS | grep -o '[0-9]\+')
           # The template is what this check verifies the committed natvis
           # file against, so take it from this PR rather than from the
           # develop checkout: generate_natvis.py loads the template from its
@@ -156,7 +150,7 @@ jobs:
           # template could never pass. Like the macro_builder step above,
           # this only renders PR content in a job without credentials.
           cp tools/generate_natvis/nlohmann_json.natvis.j2 $NATVIS_TOOL_DIR/
-          python3 $NATVIS_TOOL_DIR/generate_natvis.py --version "$VERSION_MAJOR.$VERSION_MINOR.$VERSION_PATCH" $MAIN_DIR
+          python3 $NATVIS_TOOL_DIR/generate_natvis.py $MAIN_DIR
 
       - name: Build patch and check for differences
         id: diff
@@ -165,7 +159,7 @@ jobs:
           mkdir -p ${{ github.workspace }}/patch
           git diff --patch --no-color > ${{ github.workspace }}/patch/amalgamation.patch
           if [ -s ${{ github.workspace }}/patch/amalgamation.patch ]; then
-            echo "The source code has not been amalgamated/formatted correctly or BUILD.bazel is out of date. Diff:"
+            echo "The source code has not been amalgamated/formatted correctly, or BUILD.bazel, nlohmann_json.natvis, or the macro_builder tables in macro_scope.hpp are out of date ('make amalgamate BUILD.bazel natvis' fixes all but the tables, see tools/macro_builder/README.md). Diff:"
             cat ${{ github.workspace }}/patch/amalgamation.patch
             echo "has_diff=true" >> "$GITHUB_OUTPUT"
           else