Fix compiling-as-C-pre-C99 issues

tests/test_cpp_compilation.cpp

@@ -183,6 +183,7 @@ void dummy3(void)
   stb_textedit_paste(0,0,0,0);
 }
 
+#if 0
 #define STB_C_LEX_C_DECIMAL_INTS    Y   //  "0|[1-9][0-9]*"                        CLEX_intlit
 #define STB_C_LEX_C_HEX_INTS        Y   //  "0x[0-9a-fA-F]+"                       CLEX_intlit
 #define STB_C_LEX_C_OCTAL_INTS      Y   //  "[0-7]+"                               CLEX_intlit
@@ -229,4 +230,6 @@ void dummy3(void)
 //#define STB_C_LEX_ISWHITE(str)    ... // return length in bytes of whitespace characters if first char is whitespace
 
 #define STB_C_LEXER_DEFINITIONS         // This line prevents the header file from replacing your definitions
+#endif
+
 #include "stb_c_lexer.h"