Use msginit to initialize translation files (rather than bare cp)

configure.ac

@@ -197,6 +197,11 @@ if test "x$MSGMERGE" = "x"; then
 	AC_MSG_WARN([msgmerge is not installed so translations cannot be updated])
 fi
 
+AC_PATH_PROG([MSGINIT], [msginit], [])
+if test "x$MSGINIT" = "x"; then
+	AC_MSG_WARN([msginit is not installed so new translations cannot be initialized])
+fi
+
 CAN_BUILD_PDF=${CAN_BUILD_COMMENTS}
 
 AC_PATH_PROG([CONVERT], [convert], [])

doc/Makefile.in

@@ -81,6 +81,7 @@ DBLATEX=@DBLATEX@
 
 # Gettext for translated documentation
 MSGMERGE=@MSGMERGE@
+MSGINIT=@MSGINIT@
 
 # XML gettext tools
 XML2POT=@XML2POT@
@@ -199,7 +200,7 @@ update-po: $(XML_INPUTS_POT)
       if test -f $$po; then \
         $(MSGMERGE) --update $$po $$pot; \
       else \
-        cp $$pot $$po; \
+        $(MSGINIT) -i $$pot -o $$po -l $$lang --no-translator; \
       fi; \
     done; \
   done