prevent writing beyond end of buffer

src/frontend/postsc.c

@@ -410,7 +410,8 @@ int PS_Text(const char *text_in, int x, int y, int angle)
     char *text;
     {
         const size_t n_char_text = strlen(text_in);
-        text = TMALLOC(char, n_char_text);
+        const size_t n_char_textp = n_char_text + 2;
+        text = TMALLOC(char, n_char_textp);
        utf8_to_latin9(text, text_in, n_char_text);
     }
 #endif