diff --git a/configure.ac b/configure.ac
index 1584ecb..fcc4d07 100644
--- a/configure.ac
+++ b/configure.ac
@@ -104,8 +104,14 @@ AC_CONFIG_FILES([
 AC_CONFIG_COMMANDS([default],[
 	sed -e 's%echo_source=yes%echo_source=no%g; s%src_root=.*$%%g; s%build_root=.*%%g' \
 		< metaproxy-config > src/metaproxy-config && chmod +x metaproxy-config src/metaproxy-config
-	diff doc/local.ent doc/local0.ent >/dev/null 2>/dev/null \
-		|| cp doc/local0.ent doc/local.ent
+	if ! diff doc/local.ent doc/local0.ent >/dev/null 2>/dev/null; then
+		# Reuse distributed entities through VPATH without rebuilding documentation.
+		if diff "$srcdir/doc/local.ent" doc/local0.ent >/dev/null 2>/dev/null; then
+			rm -f doc/local.ent
+		else
+			cp doc/local0.ent doc/local.ent
+		fi
+	fi
 ],[])
 AC_OUTPUT
 
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 8a37ef5..61318d8 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -131,7 +131,7 @@ dist-hook:
 	done
 
 doc-clean:
-	rm -f manref.xml *.html *.[0-9] *.?mp *.pdf toc.hhc htmlhelp.hhp local.ent
+	rm -f manref.xml *.html *.[0-9] *.?mp *.pdf toc.hhc htmlhelp.hhp
 
 install-data-hook:
 	if test -f index.html; then d=.; else d="$(srcdir)"; fi; \