patch 8.1.0597: cannot run test_libvterm from the top directory

Problem:    Cannot run test_libvterm from the top directory.
Solution:   Add test target in toplevel Makefile.
diff --git a/Makefile b/Makefile
index 4a7c4c6..3e69d45 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@
 
 # Some make programs use the last target for the $@ default; put the other
 # targets separately to always let $@ expand to "first" by default.
-all install uninstall tools config configure reconfig proto depend lint tags types test scripttests unittests testclean clean distclean:
+all install uninstall tools config configure reconfig proto depend lint tags types test scripttests test_libvterm unittests testclean clean distclean:
 	@if test ! -f src/auto/config.mk; then \
 		cp src/config.mk.dist src/auto/config.mk; \
 	fi
@@ -40,6 +40,10 @@
 	@echo "If there are problems, cd to the src directory and run make there"
 	cd src && $(MAKE) $@
 
+test: all
+	cd src && $(MAKE) test
+	cd runtime/indent && $(MAKE) clean && $(MAKE) test
+		
 
 #########################################################################
 # 2. Creating the various distribution files.
diff --git a/src/version.c b/src/version.c
index 577be31..a85295a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    597,
+/**/
     596,
 /**/
     595,