Because of commit 76eb7cef6b84ca804f4db340e23ad9c501767c32
xc_private.h now contains a definition of iovec. This conflicts
when building qemu traditional xen_platform.c which includes
hw.h which includes qemu-common.h which already has a definition
of iovec
Index: xen-4.7.0-testing/tools/libxc/xc_private.h
===================================================================
--- xen-4.7.0-testing.orig/tools/libxc/xc_private.h
+++ xen-4.7.0-testing/tools/libxc/xc_private.h
@@ -47,6 +47,8 @@
 #endif
 
 #if defined(__MINIOS__)
+#ifndef HAVE_IOVEC
+#define HAVE_IOVEC
 /*
  * MiniOS's libc doesn't know about sys/uio.h or writev().
  * Declare enough of sys/uio.h to compile.
@@ -55,6 +57,7 @@ struct iovec {
     void *iov_base;
     size_t iov_len;
 };
+#endif
 #else
 #include <sys/uio.h>
 #endif