[PATCH] Type checking for write_pda()

I just added type checking for assignments the PDA in the i386 PDA code.
Here's the x86-64 equivalent.  (Obviously this doesn't contain the latest
x86-64 PDA change.)
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andi Kleen <ak@suse.de>

include/asm-x86_64/pda.h

@@ -49,6 +49,7 @@ extern struct x8664_pda _proxy_pda;
 
 #define pda_to_op(op,field,val) do { \
 	typedef typeof(_proxy_pda.field) T__; \
+	if (0) { T__ tmp__; tmp__ = (val); }  \
 	switch (sizeof(_proxy_pda.field)) { 		\
 case 2: \
 asm(op "w %1,%%gs:%c2" : "+m" (_proxy_pda.field) : \