um: disable scan_elf_aux() on x86_64

Reusing the host's vDSO makes only sense on x86_32.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index fb2a97a..8471b81 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -21,6 +21,8 @@
 #define STACKSIZE (8 * 1024 * 1024)
 #define THREAD_NAME_LEN (256)
 
+long elf_aux_hwcap;
+
 static void set_stklim(void)
 {
 	struct rlimit lim;
@@ -143,7 +145,9 @@
 	install_fatal_handler(SIGINT);
 	install_fatal_handler(SIGTERM);
 
+#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 	scan_elf_aux(envp);
+#endif
 
 	do_uml_initcalls();
 	ret = linux_main(argc, argv);