luajit: only available on x86(-64) hosts

The -m32 compiler flag is used for 32bit builds and host-luajit has
limited architecture support. Building for a 32-bit target on a 32-bit
host should always work, but we haven't tested that and it's very
unlikely that someone needs it. So just limit to x86(-64) hosts.

Fixes:
http://autobuild.buildroot.net/results/5f5b5edb058efe976c003678e21bcc28a87cc828/

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
[Arnout: clarify that it might work on 32-bit hosts for a 32-bit target]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

(cherry picked from commit 9b9347ee9f8e531dd177b437e8ea5387e29fc35e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/luajit/Config.in

@@ -1,5 +1,8 @@
 config BR2_PACKAGE_LUAJIT_ARCH_SUPPORTS
 	bool
+	# -m32 flag is used for 32bit builds and host-luajit has
+	# limited architecture support
+	depends on BR2_HOSTARCH = "x86_64" || BR2_HOSTARCH = "x86"
 	default y if BR2_i386 || \
 		(BR2_x86_64 && BR2_HOSTARCH='x86_64') || \
 		BR2_powerpc || BR2_arm || BR2_armeb || \