Externals: add hidapi

Current master (d17db57b9d4354752e0af42f5f33007a42ef2906) because
Android support was added after the current release (0.8.0-rc1).

Externals/hidapi/udev/99-hid.rules

@@ -0,0 +1,32 @@
+# This is a sample udev file for HIDAPI devices which changes the permissions
+# to 0666 (world readable/writable) for a specified device on Linux systems.
+
+
+# If you are using the libusb implementation of hidapi (hid-libusb.c), then
+# use something like the following line, substituting the VID and PID with
+# those of your device. Note that for kernels before 2.6.24, you will need
+# to substitute "usb" with "usb_device". It shouldn't hurt to use two lines
+# (one each way) for compatibility with older systems.
+
+# HIDAPI/libusb
+SUBSYSTEM=="usb", ATTRS{idVendor}=="04d8", ATTRS{idProduct}=="003f", MODE="0666"
+
+
+# If you are using the hidraw implementation, then do something like the
+# following, substituting the VID and PID with your device. Busnum 1 is USB.
+
+# HIDAPI/hidraw
+KERNEL=="hidraw*", ATTRS{busnum}=="1", ATTRS{idVendor}=="04d8", ATTRS{idProduct}=="003f", MODE="0666"
+
+# Once done, optionally rename this file for your device, and drop it into
+# /etc/udev/rules.d and unplug and re-plug your device. This is all that is
+# necessary to see the new permissions. Udev does not have to be restarted.
+
+# Note that the hexadecimal values for VID and PID are case sensitive and
+# must be lower case.
+
+# If you think permissions of 0666 are too loose, then see:
+# http://reactivated.net/writing_udev_rules.html for more information on finer
+# grained permission setting. For example, it might be sufficient to just
+# set the group or user owner for specific devices (for example the plugdev
+# group on some systems).