*
* Thus:
* FOO matches both FOO=BAR and FOOOO=BAZ. Since the value is NULL, both these lines are removed.
- * ABC= matches both ABC=XYZ and ABC=ZYX, these lines are not copied. Instead, ABC=YYY is added.
+ * ABC= matches both ABC=XYZ and ABC=ZYX, these lines are not copied. Instead, ABC=YYY is added
+ * behind any lines that were not matched.
* ABCABC is not matched by any kv pair, so it is copied verbatim.
* The QWER= prefix is not matched by any line, so QWER=ASDF is appended to the end.
*
* The resulting file will therefore look like:
* ABCABC=QQQ
* ABC=YYY
- * 555=456
+ * QWER=ASDF
*
*/
int copy_except(FILE *in, FILE *out, struct keys_values *kv)