Add check for en_US.utf8 locale

Change-Id: I62ce7680c65ec49dd81085d4087c578f3b6c7907
Reviewed-on: https://gerrit.libreoffice.org/62508
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

configure.ac

@@ -2411,6 +2411,14 @@ if test -z "$BASH"; then
 fi
 AC_SUBST(BASH)
 
+AC_MSG_CHECKING([for en_US.utf8 locale])
+if locale -a | egrep -q 'en_US\.(UTF-8|utf8)'; then
+    AC_MSG_RESULT(present)
+else
+    AC_MSG_RESULT(absent)
+    AC_MSG_ERROR([you need en_US.utf8 locale to build])
+fi
+
 AC_MSG_CHECKING([for GNU or BSD tar])
 for a in $GNUTAR gtar gnutar bsdtar tar /usr/sfw/bin/gtar; do
     $a --version 2> /dev/null | egrep "GNU|bsdtar"  2>&1 > /dev/null