Fix:

goaewsclient.c:252:9: error: implicit declaration of function 'xmlReadMemory' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

https://gitlab.gnome.org/GNOME/gnome-online-accounts/-/commit/b9638e2418408be4906752297e700506766dcf20
--- src/goabackend/goaewsclient.c.orig
+++ src/goabackend/goaewsclient.c
@@ -27,6 +27,7 @@
 #include <glib/gi18n-lib.h>
 
 #include <libsoup/soup.h>
+#include <libxml/parser.h>
 #include <libxml/xmlIO.h>
 
 #include "goaewsclient.h"