patch 9.1.0509: not possible to translate Vim script messages

Problem:  not possible to translate Vim script messages
          (RestorerZ)
Solution: implement bindtextdomain() and gettext() to support Vim script
          message translations (Christ van Willegen)

fixes: #11637
closes: #12447

Signed-off-by: Christ van Willegen <cvwillegen@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/configure.ac b/src/configure.ac
index 946fe52..29cd926 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -4497,6 +4497,12 @@
       AC_SUBST(MAKEMO)
       dnl this was added in GNU gettext 0.10.36
       AC_CHECK_FUNCS(bind_textdomain_codeset)
+      AC_MSG_CHECKING([for dgettext])
+      AC_LINK_IFELSE([AC_LANG_PROGRAM(
+		[#include <libintl.h>],
+		[dgettext("Test", "Test");])],
+		AC_MSG_RESULT([yes]); AC_DEFINE(HAVE_DGETTEXT),
+		AC_MSG_RESULT([no]))
       dnl _nl_msg_cat_cntr is required for GNU gettext
       AC_MSG_CHECKING([for _nl_msg_cat_cntr])
       AC_LINK_IFELSE([AC_LANG_PROGRAM(