In some cases an INTEGER overflow during parsing is not detected
and incorrect value is returned to the decoder instead of an error.
Reported by Nika Pona <email@example.com>.
(Severity: low; Seuciry impact: medium).
The function `SET_OF__encode_sorted` stored the working element buffer
in a static variable. If called recursively (that is, when performing
encoding of a SET containing another SET) the outermost element buffer
is therefore clobbered by the innermost call.
This causes a SEGV on continuation of the outermost call.
Bug found during testing of [https://github.com/surevine/spiffing Spiffing],
fix verified with the same test suite.
The generated Makefile.am.example is not really in the automake style.
Renaming it to converter-example.mk to reflect that it is a plain makefile
snippet and that it is for creating the converter-example