[FS#1371] uml: fails to build with musl (fix inside)

[LEDE Bugs]

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

User who did this - Sergey (rion) 

Attached to Project - OpenWrt/LEDE Project
Summary - uml: fails to build with musl (fix inside)
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 - I have added target/linux/uml/patches-4.4/103-arch-um-compile-with-modern-headers.patch to make it compile.
the patch attached.

Tested with Lede 17.01.4

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=1371