respect user LINGUAS

--- help2man-1.46.1/Makefile.in
+++ help2man-1.46.1/Makefile.in
@@ -27,8 +27,15 @@
 export VPATH = .:$(srcdir)
 
 DESTDIR =
-LINGUAS = $(basename $(notdir $(wildcard $(srcdir)/po/*.po)))
-LINGUAS_TEXI = $(basename $(notdir $(wildcard $(srcdir)/po-texi/*.po)))
+ALL_LINGUAS = $(basename $(notdir $(wildcard $(srcdir)/po/*.po)))
+ALL_LINGUAS_TEXI = $(basename $(notdir $(wildcard $(srcdir)/po-texi/*.po)))
+ifeq ($(LINGUAS),)
+INSTALL_LINGUAS = $(ALL_LINGUAS)
+INSTALL_LINGUAS_TEXI = $(ALL_LINGUAS_TEXI)
+else
+INSTALL_LINGUAS = $(filter $(LINGUAS),$(ALL_LINGUAS))
+INSTALL_LINGUAS_TEXI = $(filter $(LINGUAS),$(ALL_LINGUAS_TEXI))
+endif
 
 CC = @CC@
 PERL = @PERL@
@@ -80,7 +87,7 @@
 
 install_l10n: install_dirs msg_l10n man_l10n info_l10n
 	set -e; \
-	for lang in $(LINGUAS); \
+	for lang in $(INSTALL_LINGUAS); \
 	do \
 	    $(MKINSTALLDIRS) $(DESTDIR)$(localedir)/$$lang/LC_MESSAGES; \
 	    $(INSTALL_DATA) $$($(FIND_VPATH) po/$$lang.gmo) \
@@ -89,7 +96,7 @@
 	    $(INSTALL_DATA) $$($(FIND_VPATH) $(target).$$lang.1) \
 		$(DESTDIR)$(mandir)/$$lang/man1/$(target).1; \
 	done; \
-	for lang in $(LINGUAS_TEXI); \
+	for lang in $(INSTALL_LINGUAS_TEXI); \
 	do \
 	    $(INSTALL_DATA) $$($(FIND_VPATH) $(target)-$$lang.info) \
 		$(DESTDIR)$(infodir)/$(target)-$$lang.info; \
@@ -151,7 +158,7 @@
 	$(MAKE) $(target) $(target).h2m
 	./$(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 $@ $?
@@ -161,7 +168,7 @@
 	$(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 $(target).%.1,%,$@); \
@@ -184,7 +191,7 @@
 $(target).info: $(srcdir)/$(target).texi
 	$(MAKEINFO) $? -o $@
 
-info_l10n: $(addprefix $(target)-,$(addsuffix .info,$(LINGUAS_TEXI)))
+info_l10n: $(addprefix $(target)-,$(addsuffix .info,$(ALL_LINGUAS_TEXI)))
 $(target)-%.info: $(target)-%.texi
 	$(MAKEINFO) $? -o $@.tmp
 	$(FIXUP_TEXI_TRANS) -o $@ $@.tmp