Move all include files to src/include

- 86Box's own headers go to /86box
- munt's public interface goes to /mt32emu
- all slirp headers go to /slirp (might want to consider using only its public inteface)
- single file headers from other projects go in include root

src/include/86box/snd_speaker.h

@@ -0,0 +1,28 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		Header of the emulation of the PC speaker.
+ *
+ *
+ *
+ * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
+ *		Miran Grca, <mgrca8@gmail.com>
+ *
+ *		Copyright 2008-2019 Sarah Walker.
+ *		Copyright 2016-2019 Miran Grca.
+ */
+extern int	speaker_mute;
+
+extern int	speaker_gated;
+extern int	speaker_enable, was_speaker_enable;
+
+
+extern void	speaker_init();
+
+extern void	speaker_set_count(uint8_t new_m, int new_count);
+extern void	speaker_update(void);