Migrate from the old curl_multi_perform() API to the newer
curl_multi_socket_action() API (since CURL 7.16).

This allows working around a bug with HTTP redirections with epoll:
when CURL closes a socket and the new one happens to have the same
file number, MPD did not have a chance to remove the old one from
epoll and subsequently attempted to use EPOLL_CTL_MOD, which was not
allowed by epoll, because it's a new socket now.

Move all global variables there, and keep just one global variable:
the pointer to the CurlMulti instance.  Prepares for the next commit.

Unused.

Eliminate some complicated code that's not worth the trouble.

Replaces the loop in input_curl_find_request().

D'oh!

Remove the forward_list::reverse() call.  It was not necessary,
because pls_parser() already reads the playlist in reverse order.

Fixes building with gcc-4.8
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>

See code comment.

First check if an IPv6 socket can be created.

Map LogLevel::INFO to G_LOG_LEVEL_INFO, and LogLevel::DEFAULT to
G_LOG_LEVEL_MESSAGE.  Now client connect/disconnect message are only
logged on log_level "secure".

Fixes bogus test failures on Debian build machines due to rounding
errors (hopefully).

Regression from previous commit.  D'oh!

Use a std::list which can be appended at the end.

getnameinfo() doesn't work well - it always returns "localhost".

This prevented using the "volume_normalization" feature with some
codecs (e.g. mp3), because the normalization code requires 16 bit
samples.  If the codec happens to deliver formats other than S16, the
AutoConvert filter succeeds to initialize the conversion filter, but
the returned input audio format was wrong.

Skip the global destructors.  We don't need them here - we bail out as
quickly as we can.

Fixes assertion failure.

mixramp_delay==nan() causes severe problems with cross-fading.

2 MB was too small for cross-fading a 24 bit file.  Increasing to 4 MB
is still not too large for weak machines, but is enough for
cross-fading.