Call sqlite3_reset() only after a sqlite3_stmt* has been used, not
before.  Assume it is already in reusable state.

SQLite 3.7.3 is the version shipped in Debian Squeeze (oldstable);
should be old enough to be the required version.  Drop the
compatibility #ifdef.

MPD used both "album artist" and "albumartist" tags and mapped them to one tag.
This could lead to issues, if a file had both tags, causing MPD to send
a list of albumartists instead of a single one.
Since "album artist" is not a standard tag anyway and even its originators
started to use the proper alternative, its time to say goodbye!

MEM_LARGE_PAGES does not appear to work.  Instead, MEM_RESERVE appears
to be necessary.  Until I figure this out, this large pages are
disabled.

Don't scan tag items if the handler doesn't implement the tag()
method.

May be more clear than operators.

Don't assume "-lpthread".  Just use PTHREAD_CFLAGS, as determined by
AX_PTHREAD.

Works around a linker problem with some older glibc versions: if
"-lrt" was used, then "-pthread" was implied, but only the symbols
used by librt were available.  This led to a linker error because
pthread_atfork() was not found.

So with "-lrt", autoconf decides that no pthread flag is necessary,
but in the end fails due to pthread_atfork() missing.

By checking for pthread before librt, we avoid this dependency
problem.