Merge branch 'refs/heads/t/rm_asn'

A few cleanups, and one patch which removes an obsolete feature,
getting rid of an open-coded ASN parser.

Cooking for three months.

* refs/heads/t/rm_asn:
  Remove unused E_PUBLIC_KEY.
  crypt.c: Combine load_key() and get_private_key().
  crypto: Remove support for ASN public keys.
  crypto: Simplify asymetric key handling.
  crypto: Rename check_key_file() -> check_private_key_file().
  gcrypt.c: Always initialize result pointer in get_private_key().

diff --combined NEWS.md
index d441db42d13aaeed62942369acef56a2fdffacae,d9326db76cfa80b50a8a268fef1b29f966cdeb09..771e12df19c0a72efe530b5d880ab375404d44e6
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -1,24 -1,9 +1,28 @@@
  NEWS
  ====
  
 +------------------------------------
 +0.6.0 (to be announced) "fuzzy flux"
 +------------------------------------
 +- Support for Mac OS X has been removed.
 +- On Linux systems, glibc-2.17 or newer is required to build the
 +  source tree.
++- Support for RSA public keys in ASN format (as generated by openssl
++  genrsa) has been removed. These keys have been deprecated since
++  2011, so users should have long switched to keys generated with
++  ssh-keygen(1).
 +
 +Downloads:
 +[tarball](./releases/paraslash-git.tar.bz2),
 +
  -------------------------------------
  0.5.7 (2016-12-31) "semantic density"
  -------------------------------------
 +
 +Mostly a bug fix release, and a bunch of internal improvements.
 +The only user-visible changes are the sanity checks for the touch
 +command and the new options to the ls command.
 +
  - Speedup of the base64 decoder.
  - One of the two source browsers has been removed from the web pages.
    The doxygen API reference still contains an HTML version of each

diff --combined error.h
index dde0122a28188dde2c36cd36e0088c6e500308f9,e6fa226a9563e77dd375dbc8200c6bfa34a3887f..f2b15a4ea7d6ce3eb09fba6c8a6baf71b5af8737
--- 1/error.h
--- 2/error.h
+++ b/error.h
@@@ -12,6 -12,7 +12,6 @@@
        PARA_ERROR(AACDEC_INIT, "failed to init aac decoder"), \
        PARA_ERROR(AAC_DECODE, "aac decode error"), \
        PARA_ERROR(ACL_PERM, "access denied by acl"), \
 -      PARA_ERROR(ADD_CALLBACK, "can not add callback"), \
        PARA_ERROR(ADDRESS_LOOKUP, "can not resolve requested address"),\
        PARA_ERROR(AFH_RECV_BAD_FILENAME, "no file name given"), \
        PARA_ERROR(AFS_SHORT_READ, "short read from afs socket"), \
@@@ -87,6 -88,7 +87,6 @@@
        PARA_ERROR(CREATE_OPUS_DECODER, "could not create opus decoder"), \
        PARA_ERROR(DCCP_OVERRUN, "dccp output buffer buffer overrun"), \
        PARA_ERROR(DECRYPT, "decrypt error"), \
 -      PARA_ERROR(DEFAULT_COMP, "can not find default audio output component"), \
        PARA_ERROR(DUMMY_ROW, "attempted to access blob dummy object"), \
        PARA_ERROR(DUP_PIPE, "exec error: can not create pipe"), \
        PARA_ERROR(EMPTY, "file is empty"), \
@@@ -175,6 -177,7 +175,6 @@@
        PARA_ERROR(OGG_PACKET_IN, "ogg_stream_packetin() failed"), \
        PARA_ERROR(OGG_STREAM_FLUSH, "ogg_stream_flush() failed"), \
        PARA_ERROR(OGG_SYNC, "internal ogg storage overflow"), \
 -      PARA_ERROR(OPEN_COMP, "OpenAComponent() error"), \
        PARA_ERROR(OPUS_COMMENT, "invalid or corrupted opus comment"), \
        PARA_ERROR(OPUS_DECODE, "opus decode error"), \
        PARA_ERROR(OPUS_HEADER, "invalid opus header"), \
@@@ -186,7 -189,6 +186,6 @@@
        PARA_ERROR(PLAY_SYNTAX, "para_play: syntax error"), \
        PARA_ERROR(PREBUFFER_SUCCESS, "prebuffering complete"), \
        PARA_ERROR(PRIVATE_KEY, "can not read private key"), \
-       PARA_ERROR(PUBLIC_KEY, "can not read public key"), \
        PARA_ERROR(QUEUE, "packet queue overrun"), \
        PARA_ERROR(READ_PATTERN, "did not read expected pattern"), \
        PARA_ERROR(RECV_EOF, "end of file"), \
@@@ -224,6 -226,7 +223,6 @@@
        PARA_ERROR(STAT_ITEM_PARSE, "failed to parse status item"), \
        PARA_ERROR(STATUS_TIMEOUT, "status item timeout"), \
        PARA_ERROR(STCO, "did not find stco atom"), \
 -      PARA_ERROR(STREAM_FORMAT, "could not set stream format"), \
        PARA_ERROR(STREAM_PACKETIN, "ogg stream packet-in error"), \
        PARA_ERROR(STREAM_PACKETOUT, "ogg stream packet-out error"), \
        PARA_ERROR(STREAM_PAGEIN, "ogg stream page-in error"), \
@@@ -239,6 -242,8 +238,6 @@@
        PARA_ERROR(TOO_MANY_CLIENTS, "maximal number of stat clients exceeded"), \
        PARA_ERROR(UCRED_PERM, "permission denied"), \
        PARA_ERROR(UDP_OVERRUN, "output buffer overrun"), \
 -      PARA_ERROR(UNIT_INIT, "AudioUnitInitialize() error"), \
 -      PARA_ERROR(UNIT_START, "AudioUnitStart() error"), \
        PARA_ERROR(UNKNOWN_STAT_ITEM, "status item not recognized"), \
        PARA_ERROR(UNSUPPORTED_AUDIO_FORMAT, "given audio format not supported"), \
        PARA_ERROR(UNSUPPORTED_FILTER, "given filter not supported"), \