vpnor: Shuffle and rework includes for sanity

Include ordering and whether or not C linkage is forced by `extern "C"`
blocks can cause headaches at link time. Ensure that all C dependencies
are included in an `extern C` block before other includes occur. Also
include the C++ versions of string.h and assert.h

Change-Id: Ia96f6044d40c8eccb907b65924efcf62ac7a89c3
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/vpnor/test/create_write_window_unmapped.cpp b/vpnor/test/create_write_window_unmapped.cpp
index e26749e..76694fc 100644
--- a/vpnor/test/create_write_window_unmapped.cpp
+++ b/vpnor/test/create_write_window_unmapped.cpp
@@ -3,10 +3,6 @@
 
 #include "config.h"
 
-#include <assert.h>
-
-#include "vpnor/mboxd_pnor_partition_table.h"
-
 extern "C" {
 #include "test/mbox.h"
 #include "test/system.h"
@@ -14,6 +10,10 @@
 
 #include "vpnor/test/tmpd.hpp"
 
+#include <cassert>
+
+#include "vpnor/mboxd_pnor_partition_table.h"
+
 static constexpr auto BLOCK_SIZE = 0x1000;
 static constexpr auto ERASE_SIZE = BLOCK_SIZE;
 static constexpr auto N_WINDOWS = 1;