Copied from Debian:

https://anonscm.debian.org/cgit/pkg-games/lierolibre.git/tree/debian/patches/0003-Remove-unknown-arch-warning.patch?id=82910748906855f6e6bfe30b3f077e8c793ae424

From a9592533eeabed075b13d11c64f63f503dc13343 Mon Sep 17 00:00:00 2001
From: Martin Erik Werner <martinerikwerner@gmail.com>
Date: Sun, 28 Jun 2015 19:31:30 +0200
Subject: [PATCH 3/3] Remove unknown arch warning

The warning was just excessivley spammy, remove it.
---
 support/platform.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/gvl/support/platform.h b/src/gvl/support/platform.h
index 1857b7c..ff6a7d2 100644
--- a/src/gvl/support/platform.h
+++ b/src/gvl/support/platform.h
@@ -87,8 +87,6 @@
 #  define GVL_X86_64 1
 # elif defined(__i386__) || defined(_M_IX86) || defined(i386) || defined(i486) || defined(intel) || defined(x86) || defined(i86pc)
 #  define GVL_X86 1
-# else
-#  warning "Unknown architecture, please add it"
 # endif
 #endif
 
-- 
2.4.6