Previously, iobuf_peek on a file smaller than 'buflen' would hang.
* common/iobuf.c (underflow): Generalize by adding a target parameter.
(iobuf_peek): Use this to prevent looping here.
* tests/openpgp/Makefile.am (TESTS): Add new test.
* tests/openpgp/setup.scm (dearmor): Move function...
* tests/openpgp/defs.scm (dearmor): ... here.
* tests/openpgp/issue2419.scm: New file.
* tests/openpgp/samplemsgs/issue2419.asc: Likewise.
GnuPG-bug-id: 2419
Signed-off-by: Justus Winter <justus@g10code.com>
