iputils: Move the iputils tools to packages

Per discussion in https://github.com/openwrt/openwrt/pull/1804, iputils is
moving from the main openwrt repository to the packages feed, and is switching
from the abandoned skbuff.net upstream to github.com/iputils/iputils

Signed-off-by: Noah Meyerhans <frodo@morgul.net>

net/iputils/Config_tracepath.in

@@ -0,0 +1,16 @@
+if PACKAGE_iputils-tracepath
+
+config TRACEPATH_LEGACY_SYMLINKS
+	bool
+	default n
+	prompt "Install legacy tracepath4 and tracepath6 symlinks"
+	help
+		Iputils previously generated separate "tracepath" and
+		"tracepath6" binaries for supporting IPv4 and IPv6
+		communication, respectively.  Recent versions of iputils
+		have merged support for both address families into a
+		single tracepath program.  Select this option to install
+		"tracepath6" and "tracepath4" symlinks to the unified
+		binary to support compatibility with existing tools that
+		may still expect to find the old names.
+endif