linux: Added Raspberry Pi kernel.

rules/linux/rpi.bash

@@ -0,0 +1,22 @@
+. "$cfg_dir_rules/$pkg/default.bash"
+
+version=\
+(
+    '3.18_2015-06-03'
+)
+
+url=\
+(
+    "https://github.com/rasmartins/rpi-linux/archive/rpi-linux-$version.tar.gz"
+)
+
+md5=\
+(
+    '0b0255e50ca358b619bb78653ac2db2e'
+)
+
+post_unpack()
+{
+    rmdir "../linux-$version" &&
+        mv "../rpi-linux-rpi-linux-$version" "../linux-$version"
+}