Make JSON_STRICT_NUL_HANDLING part of the ABI tag

JSON_STRICT_NUL_HANDLING (#5534) changes the bodies of inline functions:
the lexer's handling of '\0' and input_adapter() for char arrays. So
translation units compiled with and without it define the same functions
differently, an ODR violation - the case the ABI tag exists for, as with
JSON_BRACE_INIT_COPY_SEMANTICS (_bics). It now appends _snul to the inline
namespace. The macro is new in 3.13.0, so no existing namespace changes.

Its default moves to abi_macros.hpp, and it is only #undef'd without
JSON_TEST_KEEP_MACROS, as for the other ABI macros. The ABI config tests,
the namespace docs, the macro's docs and the Natvis file cover the new tag.

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

single_include/nlohmann/json.hpp

@@ -95,6 +95,10 @@
     #define JSON_BRACE_INIT_COPY_SEMANTICS 0
 #endif
 
+#ifndef JSON_STRICT_NUL_HANDLING
+    #define JSON_STRICT_NUL_HANDLING 0
+#endif
+
 #if JSON_DIAGNOSTICS
     #define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
 #else
@@ -119,21 +123,28 @@
     #define NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS
 #endif
 
+#if JSON_STRICT_NUL_HANDLING
+    #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING _snul
+#else
+    #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING
+#endif
+
 #ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
     #define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
 #endif
 
 // Construct the namespace ABI tags component
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d) json_abi ## a ## b ## c ## d
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d) \
-    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d)
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e) json_abi ## a ## b ## c ## d ## e
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e) \
+    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e)
 
 #define NLOHMANN_JSON_ABI_TAGS                                       \
     NLOHMANN_JSON_ABI_TAGS_CONCAT(                                   \
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS,                       \
             NLOHMANN_JSON_ABI_TAG_LEGACY_DISCARDED_VALUE_COMPARISON, \
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS,              \
-            NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS)
+            NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS,         \
+            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING)
 
 // Construct the namespace version component
 #define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \
@@ -3202,10 +3213,6 @@ void templated_json_throw(ExceptionType exception)
     #define JSON_USE_GLOBAL_UDLS 1
 #endif
 
-#ifndef JSON_STRICT_NUL_HANDLING
-    #define JSON_STRICT_NUL_HANDLING 0
-#endif
-
 #if JSON_HAS_THREE_WAY_COMPARISON
     #include <compare> // partial_ordering
 #endif
@@ -30426,7 +30433,6 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
 #undef JSON_NO_UNIQUE_ADDRESS
 #undef JSON_DISABLE_ENUM_SERIALIZATION
 #undef JSON_USE_GLOBAL_UDLS
-#undef JSON_STRICT_NUL_HANDLING
 
 #ifndef JSON_TEST_KEEP_MACROS
     #undef JSON_CATCH
@@ -30445,6 +30451,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
     #undef JSON_HAS_STATIC_RTTI
     #undef JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
     #undef JSON_BRACE_INIT_COPY_SEMANTICS
+    #undef JSON_STRICT_NUL_HANDLING
 #endif
 
 // #include <nlohmann/thirdparty/hedley/hedley_undef.hpp>

single_include/nlohmann/json_fwd.hpp

@@ -56,6 +56,10 @@
     #define JSON_BRACE_INIT_COPY_SEMANTICS 0
 #endif
 
+#ifndef JSON_STRICT_NUL_HANDLING
+    #define JSON_STRICT_NUL_HANDLING 0
+#endif
+
 #if JSON_DIAGNOSTICS
     #define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
 #else
@@ -80,21 +84,28 @@
     #define NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS
 #endif
 
+#if JSON_STRICT_NUL_HANDLING
+    #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING _snul
+#else
+    #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING
+#endif
+
 #ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
     #define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
 #endif
 
 // Construct the namespace ABI tags component
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d) json_abi ## a ## b ## c ## d
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d) \
-    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d)
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e) json_abi ## a ## b ## c ## d ## e
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e) \
+    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e)
 
 #define NLOHMANN_JSON_ABI_TAGS                                       \
     NLOHMANN_JSON_ABI_TAGS_CONCAT(                                   \
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS,                       \
             NLOHMANN_JSON_ABI_TAG_LEGACY_DISCARDED_VALUE_COMPARISON, \
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS,              \
-            NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS)
+            NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS,         \
+            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING)
 
 // Construct the namespace version component
 #define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \