tarball: include the xmlstream example

docs/examples/Makefile.inc

@@ -14,4 +14,4 @@ COMPLICATED_EXAMPLES = curlgtk.c curlx.c htmltitle.cpp cacertinmem.c	   \
   ftpuploadresume.c ghiper.c hiperfifo.c htmltidy.c multithread.c	   \
   opensslthreadlock.c sampleconv.c synctime.c threaded-ssl.c evhiperfifo.c \
   smooth-gtk-thread.c version-check.pl href_extractor.c asiohiper.cpp \
-  multi-uv.c
+  multi-uv.c xmlstream.c