[source] include: remove XZ host prereq

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/7694c5cf0edc51e7a9cea188143c6fef2f38f442

commit 7694c5cf0edc51e7a9cea188143c6fef2f38f442
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Thu Oct 6 12:13:29 2016 +0200

    include: remove XZ host prereq
    
    We build XZ as part of tools/, so no need to require it to be available
    on the host system.
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 include/prereq-build.mk | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/prereq-build.mk b/include/prereq-build.mk
index b2f5699..4a0509a 100644
--- a/include/prereq-build.mk
+++ b/include/prereq-build.mk
@@ -164,9 +164,6 @@ $(eval $(call SetupHostCommand,git,Please install Git (git-core) >= 1.7.12.2, \
 $(eval $(call SetupHostCommand,file,Please install the 'file' package, \
 	file --version 2>&1 | grep file))
 
-$(eval $(call SetupHostCommand,xz,Please install xz-utils, \
-	xz --version | grep XZ))
-
 ifneq ($(HOST_OS),Darwin)
 $(eval $(call SetupHostCommand,openssl,Please install the 'openssl' utility, \
 	openssl version | grep '\(OpenSSL\|LibreSSL\)'))