playlist_edit: Don't stop the player when deleting current song

Because doing this would stop the httpd, icecast, etc. streaming.
todo: update tode.
Merge branch 'err'

This seems to be generally working, I've run this branch for several
weeks without obvious problems.
resolver: minor fix.
modplug: fix include dir

Should I write a configure check for this?
spl: fix typo in spl_map_to_fs

Also fix several log with non-literal string in stored_playlist.c.
utils: fix va_args reuse

Don't use va_args again after passing it to vnsprintf.
gme, flac: Fix check of return value
decoder_thread: Fix error handling
decode: asap: Fix leaking file descriptor
update: Fix crash
update_container: Fix double unlock
Switching to cmake.

A few notes:

1) I re-organized the directory structure in the process.

2) Archive plugin is not included for now. Major refactoring require for
archive plugins. Plan is to convert archive plugins to input plugins.

3) Eerything that does not have external dependencies are always
enabled. I've gone through the code, those features will not increase
the result executable size too much.

The conversion to cmake is considered done by now. Future changes will
be in separate commits.
Add check for Solaris
Add check for large file support
Remove check.h

Now all large file related definitions are included in CFLAGS.