fixing the buffer overrun, as this fix was lost with this revert.

This reverts commit 615295a4.

Merging minor security fix (#318)

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.

zeroed repeat. Fix takes value of repeat.

Add aper encoder for SET_OF

similar fix for OCTET STRING)

Add EXTERNAL support

- Remove EXTERNAL from asn1p_l.l and asn1p_y.y
- Add EXTERNAL ASN.1 definition from ITU-T X.208 in
  skeletons/standard-modules/ASN1C-UsefulInformationObjectClasses.asn1
- Add a test case:
  tests/tests-asn1c-compiler/159-EXTERNAL-OK.asn1
  tests/tests-c-compiler/check-src/check-159.c
- Regenerate all tests/tests-asn1c-compiler/*.asn1.* files

Remove asn1p_l.c, asn1p_y.c and asn1_p.h from the repository.
https://www.gnu.org/software/automake/manual/html_node/Yacc-and-Lex.html
https://www.gnu.org/software/automake/manual/html_node/Built-Sources-Example.html#Built-Sources-Example

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.

in calculations when gmtoff was not initialized before first use

Mimic what OAI's asnfix.c of generate_asn1 script does.

Mimic what OAI's asnfix.c of generate_asn1 script does.