respect user LINGUAS

+++ b/Makefile.in
@@ -16,7 +16,12 @@
 export VPATH = .:$(srcdir)
 
 DESTDIR =
-LINGUAS = $(basename $(notdir $(wildcard $(srcdir)/po/*.po)))
+ALL_LINGUAS = $(basename $(notdir $(wildcard $(srcdir)/po/*.po)))
+ifeq ($(LINGUAS),)
+INSTALL_LINGUAS = $(ALL_LINGUAS)
+else
+INSTALL_LINGUAS = $(filter $(LINGUAS),$(ALL_LINGUAS))
+endif
 
 CC = @CC@
 PERL = @PERL@
@@ -56,7 +62,7 @@
 	$(INSTALL_PROGRAM) $(preload).so $(DESTDIR)$(pkglibdir)
 
 install_l10n: install_dirs msg_l10n man_l10n
-	for lang in $(LINGUAS); \
+	for lang in $(INSTALL_LINGUAS); \
 	do \
 	    $(MKINSTALLDIRS) $(DESTDIR)$(localedir)/$$lang/LC_MESSAGES; \
 	    $(INSTALL_DATA) $(call vpath_file,po/$$lang.gmo) \
@@ -124,7 +130,7 @@
 	$(MAKE) $(target).h2m
 	./$(target) --include=$(target).h2m --output=$@ ./$(target)
 
-msg_l10n: $(addprefix po/,$(addsuffix .gmo,$(LINGUAS)))
+msg_l10n: $(addprefix po/,$(addsuffix .gmo,$(ALL_LINGUAS)))
 po/%.gmo: $(srcdir)/po/%.po
 	test -d po || mkdir po
 	$(MSGFMT) -o $@ $?
@@ -134,7 +140,7 @@
 	$(MKINSTALLDIRS) localetmp/$$lang/LC_MESSAGES && \
 	$(INSTALL_DATA) po/$$lang.gmo localetmp/$$lang/LC_MESSAGES/$(target).mo
 
-man_l10n: $(addprefix $(target).,$(addsuffix .1,$(LINGUAS)))
+man_l10n: $(addprefix $(target).,$(addsuffix .1,$(ALL_LINGUAS)))
 $(target).%.1: $(srcdir)/$(target).PL $(srcdir)/$(target).h2m.PL \
     $(srcdir)/po/%.po
 	lang=$(patsubst $(target).%.1,%,$@); \
@@ -164,7 +170,7 @@
 	./config.status
 
 update-po: $(srcdir)/po/$(target).pot
-	for lang in $(LINGUAS); \
+	for lang in $(ALL_LINGUAS); \
 	do \
 	    echo -n "Updating $$lang "; \
 	    msgmerge -U $(srcdir)/po/$$lang.po $(srcdir)/po/$(target).pot; \