libatomic_ops: make it available only on supported architectures

libatomic_ops build fails on architectures such as MIPS or SuperH that
are not supported. So we make it possible to select the libatomic_ops
package only for the architectures that are known to be supported.

[Peter: add armeb as supported arch]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/libatomic_ops/Config.in

@@ -1,4 +1,5 @@
 config BR2_PACKAGE_LIBATOMIC_OPS
 	bool "libatomic_ops"
+	depends on BR2_arm || BR2_armeb || BR2_i386 || BR2_sparc || BR2_powerpc || BR2_x86_64
 	help
 	  Atomic operations library

package/libdrm/Config.in

@@ -8,7 +8,10 @@ config BR2_PACKAGE_LIBDRM
 	select BR2_PACKAGE_XLIB_LIBXMU
 	select BR2_PACKAGE_XPROTO_DRI2PROTO
 	select BR2_PACKAGE_PTHREAD_STUBS
-	select BR2_PACKAGE_LIBATOMIC_OPS if BR2_PACKAGE_XDRIVER_XF86_VIDEO_INTEL
+	# libatomic_ops is only available on a subset of the supported
+	# architectures, and we make the assumption that the intel
+	# driver can only be used on x86 and x86_64 machines.
+	select BR2_PACKAGE_LIBATOMIC_OPS if (BR2_PACKAGE_XDRIVER_XF86_VIDEO_INTEL && (BR2_i386 || BR2_x86_64))
 	help
 	  Direct Rendering Manager