asm/paravirt.h ends up including linux/sched.h, which pud_populate needs
for its reference to current.  Specifically include linux/sched.h for it.

In file included from /home/jeremy/hg/xen/paravirt/linux/arch/x86/mm/pgtable.c:3:
include2/asm/pgalloc.h: In function ‘pud_populate’:
include2/asm/pgalloc.h:93: error: dereferencing pointer to incomplete type
make[3]: *** [arch/x86/mm/pgtable.o] Error 1
make[2]: *** [arch/x86/mm/] Error 2
make[1]: *** [sub-make] Error 2
make: *** [all] Error 2

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/pgalloc.h |    1 +
 1 file changed, 1 insertion(+)

diff --git a/include/asm-x86/pgalloc.h b/include/asm-x86/pgalloc.h
--- a/include/asm-x86/pgalloc.h
+++ b/include/asm-x86/pgalloc.h
@@ -4,6 +4,7 @@
 #include <linux/threads.h>
 #include <linux/mm.h>		/* for struct page */
 #include <linux/pagemap.h>
+#include <linux/sched.h>
 
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>