Don't use qemu_build_not_reached with Clang
Clang generates a reference to qemu_build_not_reached breaking the link.
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index c76281f..e9c8ec1 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -236,7 +236,7 @@
* supports QEMU_ERROR, this will be reported at compile time; otherwise
* this will be reported at link time due to the missing symbol.
*/
-#if defined(__OPTIMIZE__) && !defined(__NO_INLINE__)
+#if defined(__OPTIMIZE__) && !defined(__NO_INLINE__) && !defined(__clang__)
extern void QEMU_NORETURN QEMU_ERROR("code path is reachable")
qemu_build_not_reached(void);
#else
