[FS#213] Inlcuding iputils-traceroute6 in image breaks the build

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - silentcreek (silentcreek) 

Attached to Project - LEDE Project
Summary - Inlcuding iputils-traceroute6 in image breaks the build
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Out of habit, I tried to compile LEDE including the package iputils-traceroute6. It took me several attempts to realize that this breaks the build. The package iputils-traceroute6 conflicts with busybox which already includes a traceroute6 utility. The (shortened) output of 'make -j1 V=s' looks like this:
[...]
Installing sqm-scripts (1.0.8-1) to root...
Installing luci-app-sqm (1.0.8-1) to root...
Collected errors:
 * check_data_file_clashes: Package busybox wants to install file /home/user/LEDE/tmp/build_dir/target-mips_24kc_musl-1.1.15/root-ar71xx/usr/bin/traceroute6
	But that file is already provided by package  * iputils-traceroute6
 * opkg_install_cmd: Cannot install package busybox.
Configuring libgcc.
Configuring libc.
[...]
Configuring ppp-mod-pppoe.
Configuring dnsmasq-full.
package/Makefile:56: recipe for target 'package/install' failed
make[2]: *** [package/install] Error 255
make[2]: Leaving directory '/home/user/LEDE/tmp'
package/Makefile:125: recipe for target '/home/user/LEDE/tmp/staging_dir/target-mips_24kc_musl-1.1.15/stamp/.package_install' failed
make[1]: *** [/home/user/LEDE/tmp/staging_dir/target-mips_24kc_musl-1.1.15/stamp/.package_install] Error 2
make[1]: Leaving directory '/home/user/LEDE/tmp'
/home/user/LEDE/tmp/include/toplevel.mk:193: recipe for target 'world' failed
make: *** [world] Error 2

I used to comile my images with the package iputils-traceroute6 because in OpenWrt Chaos Calmer, there was no traceroute6 utility included. Now I know that this is not neccessary anymore, but nevertheless, in my opinion, the package iputils-traceroute6 should not be selectable when busybox is selected. The reason it took me while to realize the reason for the build error is that the first error ("Cannot install package busybox") does not actually break the build but that only happens later (there are more than 100 lines in the build log between this error and the final message "make: *** [world] Error 2"), so I first looked in the wrong direction (only at the last lines).

The diffconfig I used for the build is attached. The LEDE revision built was r1742.

One or more files have been attached.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=213