Removed the NULL check.

This fixes a NULL pointer dereference in case of archive plugin
failure.

Make archive_file a "real" struct, extended by all plugins.  Add the
plugin pointer to it.  Wrap all method calls in functions.

Moved the archive plugin "extern" declarations into each plugin
header.

Use the raw struct name instead.

Based on libiso9660.

Use g_path_get_basename() instead of manually filtering the path
name.  Big advantage: g_path_get_basename() cannot fail.

For the fluidsynth plugin.

This fixes a regression: a boolean value was returned from
decoder_input_buffer(), but the caller chose to do a "<= 0"
comparison.

.. instead of manually checking pathname[0]=='/'.
g_path_is_absolute() is portable.

Don't attempt to fill the whole buffer in the read() method, return
whatever libbz2 provides with the first successful BZ2_bzDecompress().

Use the raw struct name.

This plugin is based on libzzip.

Conflicts:
	src/archive/bz2_plugin.c
	src/archive_api.h
	src/input/file_input_plugin.c
	test/run_input.c

Free the "context" pointer in the method archive_plugin.close().

Fixes a memory leak: the "archive" input plugin opens the archive, but
never closes it.  This patch moves the responsibility for doing that
to archive_plugin.open_stream().  This is an slight internal API
change, but it is the simplest and least intrusive fix for the memory
leak.

g_free(NULL) is allowed.

Fixed memory leak in error handler.

This enables valgrind debugging after an error occurred.

Enable archive plugin debugging.

This code has never made any sense, and has broken some of the archive
plugin.

This code has never made any sense, and has broken some of the archive
plugin.

Use struct forward declarations.

Don't use num_archive_plugins.

This fixes "make distcheck".

Removed local variable "sample_rate".