diff --git a/Makefile.am b/Makefile.am
index bd78f444c50..2e4f8573845 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4735,7 +4735,7 @@ CLEANFILES += \
 
 # ------------------------------------------------------------------------------
 if ENABLE_MANPAGES
-man/custom-entities.ent:
+man/custom-entities.ent: configure.ac
 	$(AM_V_GEN)$(MKDIR_P) $(dir $@)
 	$(AM_V_GEN)(echo '<?xml version="1.0" encoding="utf-8" ?>' && \
 	 printf '$(subst '|,<!ENTITY ,$(subst =, ",$(subst |',">\n,$(substitutions))))') \