🚸 add check if different version is also included #3337 (#3418)

doc/mkdocs/docs/features/macros.md

@@ -125,6 +125,19 @@ security reasons (e.g., Intel Software Guard Extensions (SGX)).
     #undef JSON_NO_IO
     ```
 
+## `JSON_SKIP_LIBRARY_VERSION_CHECK`
+
+When defined, the library will not create a compiler warning when a different version of the library was already
+included.
+
+!!! info "Default behavior"
+
+    By default, the macro is not defined.
+
+    ```cpp
+    #undef JSON_SKIP_LIBRARY_VERSION_CHECK
+    ```
+
 ## `JSON_SKIP_UNSUPPORTED_COMPILER_CHECK`
 
 When defined, the library will not create a compile error when a known unsupported compiler is detected. This allows to

include/nlohmann/json.hpp

@@ -39,6 +39,14 @@ SOFTWARE.
 #ifndef INCLUDE_NLOHMANN_JSON_HPP_
 #define INCLUDE_NLOHMANN_JSON_HPP_
 
+#ifndef JSON_SKIP_LIBRARY_VERSION_CHECK
+    #if defined(NLOHMANN_JSON_VERSION_MAJOR) && defined(NLOHMANN_JSON_VERSION_MINOR) && defined(NLOHMANN_JSON_VERSION_PATCH)
+        #if NLOHMANN_JSON_VERSION_MAJOR != 3 || NLOHMANN_JSON_VERSION_MINOR != 10 || NLOHMANN_JSON_VERSION_PATCH != 5
+            #warning "Already included a different version of the library!"
+        #endif
+    #endif
+#endif
+
 #define NLOHMANN_JSON_VERSION_MAJOR 3
 #define NLOHMANN_JSON_VERSION_MINOR 10
 #define NLOHMANN_JSON_VERSION_PATCH 5

single_include/nlohmann/json.hpp

@@ -39,6 +39,14 @@ SOFTWARE.
 #ifndef INCLUDE_NLOHMANN_JSON_HPP_
 #define INCLUDE_NLOHMANN_JSON_HPP_
 
+#ifndef JSON_SKIP_LIBRARY_VERSION_CHECK
+    #if defined(NLOHMANN_JSON_VERSION_MAJOR) && defined(NLOHMANN_JSON_VERSION_MINOR) && defined(NLOHMANN_JSON_VERSION_PATCH)
+        #if NLOHMANN_JSON_VERSION_MAJOR != 3 || NLOHMANN_JSON_VERSION_MINOR != 10 || NLOHMANN_JSON_VERSION_PATCH != 5
+            #warning "Already included a different version of the library!"
+        #endif
+    #endif
+#endif
+
 #define NLOHMANN_JSON_VERSION_MAJOR 3
 #define NLOHMANN_JSON_VERSION_MINOR 10
 #define NLOHMANN_JSON_VERSION_PATCH 5

third_party/amalgamate/amalgamate.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # coding=utf-8
 
 # amalgamate.py - Amalgamate C source and header files.