Add #undef __user before and after including compiler_types.h to avoid
redefinition warnings when compiling with system headers that also
define __user. This allows tools/virtio to build without warnings.

Additionally, stub out __must_check

Created using Cursor CLI.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/linux/compiler.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/virtio/linux/compiler.h b/tools/virtio/linux/compiler.h
index 204ef0e9f542..7f9e308f3880 100644
--- a/tools/virtio/linux/compiler.h
+++ b/tools/virtio/linux/compiler.h
@@ -2,7 +2,11 @@
 #ifndef LINUX_COMPILER_H
 #define LINUX_COMPILER_H
 
+/* Avoid redefinition warnings */
+#undef __user
 #include "../../../include/linux/compiler_types.h"
+#undef __user
+#define __user
 
 #define WRITE_ONCE(var, val) \
 	(*((volatile typeof(val) *)(&(var))) = (val))
@@ -35,4 +39,6 @@
 	__v;								\
 })
 
+#define __must_check
+
 #endif
-- 
MST