The file json.tab.c contains two instances of "typedef union YYSTYPE YYSTYPE;", which is an error in C standards prior to C11:

json.tab.c:136:23: error: redefinition of typedef 'YYSTYPE' is invalid in C [-Wtypedef-redefinition]
typedef union YYSTYPE YYSTYPE;
                      ^

Specifically encountered on macOS using an older Xcode clang version that defaults to C99.