Bug 721158: Missing ICU string when doing --version on xmllint <https://bugzilla.gnome.org/show_bug.cgi?id=721158>

* xmllint.c:
(showVersion): Add "ICU" to xmllint version string if libxml2 is
built with ICU enabled.
diff --git a/xmllint.c b/xmllint.c
index 1e2eb4a..7c61286 100644
--- a/xmllint.c
+++ b/xmllint.c
@@ -2967,6 +2967,7 @@
     if (xmlHasFeature(XML_WITH_XPTR)) fprintf(stderr, "XPointer ");
     if (xmlHasFeature(XML_WITH_XINCLUDE)) fprintf(stderr, "XInclude ");
     if (xmlHasFeature(XML_WITH_ICONV)) fprintf(stderr, "Iconv ");
+    if (xmlHasFeature(XML_WITH_ICU)) fprintf(stderr, "ICU ");
     if (xmlHasFeature(XML_WITH_ISO8859X)) fprintf(stderr, "ISO8859X ");
     if (xmlHasFeature(XML_WITH_UNICODE)) fprintf(stderr, "Unicode ");
     if (xmlHasFeature(XML_WITH_REGEXP)) fprintf(stderr, "Regexps ");