Many years ago, FAAD had a serious ABI bug: the NeAACDecInit()
prototype in its header declared the "samplerate" parameter to be
"unsigned long *", but internally, the function assumed it was
"uint32_t *" instead. On 32 bit machines, that was no difference, but
on 64 bit, this left one portion of the return value uninitialized;
and worse, on big-endian, the wrong word was filled. This bug had to
be worked around in MPD (commit 9c4e97a6).
A few months later, the bug was fixed in the FAAD CVS in commit 1.117
on file libfaad/decoder.c; the commit message was:
"Use public headers internally to prevent duplicate declarations"
The commit message was too brief at best; the problem was not
duplicate declarations, but a prototype mismatch. No mention of the
bug fix in the ChangeLog.
The MPD project never learned about this bug fix, and so MPD would
always pass a "uin32_t *" dressed up as a "unsigned long *". Nearly 6
years later, it's about time to fix this second ABI problem. Let's
kill the workaround!
This change adds two configuration options:
--with-eventloop=[glib|internal|auto]
--with-pollmethod=[epoll|auto]
First allows switching between GLib event loop and internal one.
Second chooses backend to use for internal event loop.
Conditional compilation symbols are changed accordingly.
Additional helper macro MPD_OPTIONAL_FUNC_NODEF is added as well.
Remove the runtime check for eventfd(), hard-code the feature once
it's been selected at compile time. The class WakeFD is splitted into
EventFD and EventPipe, using WakeFD as a macro diversion.
The M4 function AM_PATH_LAME (m4/lame.m4) defined a configure flag
named "--disable-lametest". This is redundant with configure.ac's
--disable-lame-encoder, and specifying both options may break the
build. Since AM_PATH_LAME is only called when the encoder plugin is
enabled, we can safely remove that --disable-lametest option.
When MPD_AUTO_DISABLED prints a fatal error message, include the
feature name. This might be an important piece of information for the
user, just in case the preceding line doesn't tell him.
This patch adds a small autoconf M4 library which deals with
auto-detected features. The default for those features is "auto",
which is like the old default: if the library is present on the
system, enable the feature, disable otherwise. If the user explicitly
enables that feature (--enable-alsa), and the library is not present,
configure must fail, because it cannot fulfill the request.
