Fix x86 user_regs_struct.

I fixed x86-64 yesterday, but didn't fix x86 at the same time.

Change-Id: I5c081f5956dfedb9389af303369b841dd0fc1953
diff --git a/libc/include/sys/user.h b/libc/include/sys/user.h
index bf762e7..9f11a83 100644
--- a/libc/include/sys/user.h
+++ b/libc/include/sys/user.h
@@ -61,23 +61,23 @@
   long padding[56];
 };
 struct user_regs_struct {
-  unsigned long bx;
-  unsigned long cx;
-  unsigned long dx;
-  unsigned long si;
-  unsigned long di;
-  unsigned long bp;
-  unsigned long ax;
-  unsigned long ds;
-  unsigned long es;
-  unsigned long fs;
-  unsigned long gs;
-  unsigned long orig_ax;
-  unsigned long ip;
-  unsigned long cs;
-  unsigned long flags;
-  unsigned long sp;
-  unsigned long ss;
+  long ebx;
+  long ecx;
+  long edx;
+  long esi;
+  long edi;
+  long ebp;
+  long eax;
+  long xds;
+  long xes;
+  long xfs;
+  long xgs;
+  long orig_eax;
+  long eip;
+  long xcs;
+  long eflags;
+  long esp;
+  long xss;
 };
 struct user {
   struct user_regs_struct regs;