simple cleanups in defs.h. No logic changes.

* defs.h: Move offsetof macro definition into "libc stuff" section.
Renumber TCB_foo constants (smaller constants -> sometimes smaller code).
Remove uoff macro.
* process.c: Move uoff macro here (sole user).

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/process.c b/process.c
index ab667e2..100ccd4 100644
--- a/process.c
+++ b/process.c
@@ -1287,6 +1287,8 @@
 };
 #endif /* PTRACE_SETOPTIONS */
 
+#define uoff(member)	offsetof(struct user, member)
+
 const struct xlat struct_user_offsets[] = {
 #if defined(S390) || defined(S390X)
 	{ PT_PSWMASK,		"psw_mask"				},