Use make functions for HELP_LINGUAS

Author: raveit65

help/Makefile.am

@@ -6,6 +6,10 @@ HELP_ID = atril
 HELP_FILES = index.docbook legal.xml
 HELP_MEDIA = figures/atril_start_window.png
 
-HELP_LINGUAS = bg ca cs de el en_GB es eu fi fr it ja nl oc pt_BR ru sl sr sv uk vi zh_CN
+# Add linguas to be ignored, e.g. IGNORE_HELP_LINGUAS = ca de es fr
+IGNORE_HELP_LINGUAS =
+HELP_LINGUAS = $(if $(IGNORE_HELP_LINGUAS), \
+	$(filter-out $(IGNORE_HELP_LINGUAS),$(subst /,,$(dir $(wildcard */*.po)))), \
+	$(subst /,,$(dir $(wildcard */*.po))) )
 
 -include $(top_srcdir)/git.mk