x86, um: initial part of asm-um move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/um/include/asm/desc.h

@@ -0,0 +1,16 @@
+#ifndef __UM_DESC_H
+#define __UM_DESC_H
+
+/* Taken from asm-i386/desc.h, it's the only thing we need. The rest wouldn't
+ * compile, and has never been used. */
+#define LDT_empty(info) (\
+	(info)->base_addr	== 0	&& \
+	(info)->limit		== 0	&& \
+	(info)->contents	== 0	&& \
+	(info)->read_exec_only	== 1	&& \
+	(info)->seg_32bit	== 0	&& \
+	(info)->limit_in_pages	== 0	&& \
+	(info)->seg_not_present	== 1	&& \
+	(info)->useable		== 0	)
+
+#endif