Fix CI on develop (#5750)

* Fix CI configuration broken by recent merges and tool updates

- gcc_flags.cmake: drop -Wexperimental-fmv-target, which GCC 16 accepts
  only on aarch64; amd64 rejects it, so every GCC job failed while
  checking the compiler.
- ci_get_cmake: add VERBATIM so the checksum pipeline is passed to the
  shell intact (the unescaped `$'` broke the generated Makefile and
  build.ninja, failing ci_cmake_flags and ci_module_cpp20); match the
  SHA-256 entry case-insensitively, as CMake 3.5.0 lists the archive as
  "Linux-x86_64"; and unpack with --strip-components, as that archive's
  top-level directory is spelled "Linux" too.
- ci_single_binaries: compile json.hpp's TU without IWYU's --error, as
  the comment above the gate already intends.
- tests: restore -Wno-deprecated-declarations for all non-MSVC compilers
  (#5737 kept it for GCC only), as several tests call deprecated
  functions on purpose; include thirdparty/fifo_map as SYSTEM.
- .clang-tidy: set misc-use-internal-linkage.AnalyzeTypes to false;
  clang-tidy 22.1 extended the check to classes and enums and flagged
  100 test helper types.

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

* Fix library warnings and a JSON_DIAGNOSTICS parent bug

- binary_reader: pass integers to sax->number_integer() through
  conditional_static_cast<number_integer_t>, making the existing
  narrowing for a narrow number_integer_t explicit (MSVC C4244 and GCC
  -Wconversion/-Warith-conversion with the int16_t test from #5694);
  mark two Infer DEAD_STORE false positives with @infer-ignore.
- to_json: set the parents of an array built from a C++20 range view
  after all elements are in place; a reallocating push_back moved the
  earlier elements and left their parent pointers stale, failing the
  JSON_DIAGNOSTICS invariant assertion.
- json.hpp: suppress MSVC C4127 for the new is_ordered_map check in
  diff(), like the three existing ones; spell out std::formatter::parse's
  return and iterator types for clang-tidy 22.1.
- number_parse: make the Eisel-Lemire digit counter unsigned
  (GCC -Wstrict-overflow).
- string_utils: take encode_utf8's callable by const reference
  (cppcoreguidelines-missing-std-forward) and drop a \u from its doc
  comment (-Wdocumentation-unknown-command).
- ordered_map: include <memory> for std::allocator (cpplint).

Ran make amalgamate.

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

* Fix tests failing in CI on develop

- unit-allocator: skip the #5640 test under MSVC STL iterator debugging,
  where containers allocate a debug proxy in noexcept move constructors
  and a failing allocation terminates; move a decrement out of an if
  condition (bugprone-inc-dec-in-conditions).
- unit-conversions: expect the "(/0)" path with JSON_DIAGNOSTICS;
  compare strict enums via get<>() rather than through the noexcept
  operator==(ScalarType, json), which bugprone-exception-escape flags.
- unit-alt-string: suppress -Wexit-time-destructors for the strict enum
  macro and misc-use-internal-linkage for its enum.
- unit-bjdata: call the static lookup functions through the type and
  pass unsigned char (-Wsign-conversion on amd64).
- Mark Infer false positives with @infer-ignore in unit-diagnostics,
  unit-pointer_access, unit-udt, and unit-conversions.
- Smaller clang-tidy 22.1 findings in unit-class_parser,
  unit-constructor2, unit-custom-base-class, unit-locale-cpp, and
  unit-noexcept.

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

---------

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

tests/src/unit-alt-string.cpp

@@ -16,6 +16,10 @@
 #include <utility>
 #include <vector>
 
+// NLOHMANN_JSON_SERIALIZE_ENUM_STRICT uses a static std::pair
+DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
+DOCTEST_CLANG_SUPPRESS_WARNING("-Wexit-time-destructors")
+
 /* forward declarations */
 class alt_string;
 bool operator<(const char* op1, const alt_string& op2) noexcept; // NOLINT(misc-use-internal-linkage)
@@ -174,7 +178,7 @@ bool operator<(const char* op1, const alt_string& op2) noexcept
     return op1 < op2.str_impl;
 }
 
-enum class alt_color { red, green };
+enum class alt_color { red, green }; // NOLINT(misc-use-internal-linkage)
 
 // NOLINTNEXTLINE(misc-use-internal-linkage,misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays) - false positive
 NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(alt_color,
@@ -434,3 +438,5 @@ TEST_CASE("alternative string type")
         CHECK_THROWS_WITH_AS(_ = doc.get<alt_color>(), "[json.exception.out_of_range.410] enum value out of range for alt_color: \"blue\"", alt_json::out_of_range&);
     }
 }
+
+DOCTEST_CLANG_SUPPRESS_WARNING_POP