sane-backends: import from oldpackages and update

Changes since oldpackages:
- updated to 1.0.25
  * most of openwrt patches are upstreamed now
- cups dependency was completely removed
- small musl patch
- small uclibc patch
- removed link to extra libraries in libsane (used only
  for preload backends)
- sane-libs and sane-backends merged and exploded into
  individual packages for each backend:
  * libsane for sane library (which backends should dep on)
  * sane-daemon for saned daemon
  * sane-xxx for sane backend for xxx
  ** each backend has its own custom dep libraries
  * sane-backends-all (with no files) that deps on all backends
  * sane-qcam is only available for x86/x86_64
  ** other archs does not implement inb/outb (at least in musl)

Now it is possible to use SANE with much less FS space (KB
instead of MB).

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>

utils/sane-backends/patches/020-fix_pieusb.patch

@@ -0,0 +1,16 @@
+--- a/backend/pieusb_buffer.c
++++ b/backend/pieusb_buffer.c
+@@ -104,11 +104,13 @@
+ 
+ /* When creating the release backend, make complains about unresolved external
+  * le16toh, although it finds the include <endian.h> */
++#ifndef le16toh
+ #if __BYTE_ORDER == __LITTLE_ENDIAN
+  #define le16toh(x) (x)
+ #else
+  #define le16toh(x) __bswap_16 (x)
+ #endif
++#endif
+ 
+ static void buffer_update_read_index(struct Pieusb_Read_Buffer* buffer, int increment);
+