fix(jsoncpp): compile library with C++20 support

Author: Michael Bleis

CMakeLists.txt

@@ -40,9 +40,9 @@ foreach(pold "") # Currently Empty
     endif()
 endforeach()
 
-# Build the library with C++11 standard support, independent from other including
+# Build the library with C++20 standard support, independent from other including
 # software which may use a different CXX_STANDARD or CMAKE_CXX_STANDARD.
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 

include/json/value.h

@@ -39,7 +39,9 @@
 #endif
 #endif
 
+#if __cplusplus >= 201703L
 #define JSONCPP_HAS_STRING_VIEW 1
+#endif
 
 #include <array>
 #include <exception>