server: Fix 64-bit alignment of the context structure.
diff --git a/server/protocol.def b/server/protocol.def
index 0aa8f6c..4aaff10 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -158,10 +158,10 @@
     {
         struct { unsigned int eip, ebp, esp, eflags, cs, ss; } i386_regs;
         struct { unsigned __int64 rip, rbp, rsp;
-                 unsigned int cs, ss, flags; } x86_64_regs;
+                 unsigned int cs, ss, flags, __pad; } x86_64_regs;
         struct { unsigned __int64 fir;
-                 unsigned int psr; } alpha_regs;
-        struct { unsigned int iar, msr, ctr, lr, dar, dsisr, trap; } powerpc_regs;
+                 unsigned int psr, __pad; } alpha_regs;
+        struct { unsigned int iar, msr, ctr, lr, dar, dsisr, trap, __pad; } powerpc_regs;
         struct { unsigned int psr, pc, npc, y, wim, tbr; } sparc_regs;
     } ctl;  /* selected by SERVER_CTX_CONTROL */
     union