default SET_PERSONALITY() in linux/elf.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 8c9048e..40a3c0e0 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -10,6 +10,10 @@
      Override in asm/elf.h as needed.  */
 # define elf_read_implies_exec(ex, have_pt_gnu_stack)	0
 #endif
+#ifndef SET_PERSONALITY
+#define SET_PERSONALITY(ex) \
+	set_personality(PER_LINUX | (current->personality & (~PER_MASK)))
+#endif
 
 #if ELF_CLASS == ELFCLASS32