The SYS_ constants should cover all __NR_ values.

<sys/linux-syscalls.h> only contains constants for the syscalls
we're generating stubs for. We want all the syscalls available
on the architecture in question.

Keep using <sys/linux-syscalls.h> on ARM for now because the
__NR_ARM_set_tls and __NR_ARM_cacheflush values aren't in <asm/unistd.h>.

Change-Id: I66683950d87d9b18d6107d0acc0ed238a4496f44
diff --git a/libc/arch-x86/bionic/vfork.S b/libc/arch-x86/bionic/vfork.S
index 235be0c..7b62449 100644
--- a/libc/arch-x86/bionic/vfork.S
+++ b/libc/arch-x86/bionic/vfork.S
@@ -1,10 +1,5 @@
 #include <machine/asm.h>
-#include <sys/linux-syscalls.h>
-
-#ifndef __NR_vfork
-#define __NR_vfork  190
-#endif
-
+#include <asm/unistd.h>
 
 /* Get rid of the stack modifications (popl/ret) after vfork() success.
  * vfork is VERY sneaky. One has to be very careful about what can be done