patch 8.2.5031: cannot easily run the benchmarks

Problem:    Cannot easily run the benchmarks.
Solution:   Have "make benchmark" in the src directory work.
diff --git a/src/Makefile b/src/Makefile
index d15e314..9399121 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2245,8 +2245,11 @@
 testtiny:
 	cd testdir; $(MAKE) -f Makefile tiny VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
 
+# Run benchmarks.
 benchmark:
-	cd testdir; $(MAKE) -f Makefile benchmark VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
+	cd testdir; \
+		$(MAKE) -f Makefile benchmarkclean; \
+		$(MAKE) -f Makefile benchmark VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
 
 unittesttargets:
 	$(MAKE) -f Makefile $(UNITTEST_TARGETS)
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index c54e060..c782da9 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -90,6 +90,10 @@
 	-rm -f valgrind.*
 	-rm -f asan.*
 
+# Delete the files produced by benchmarking, so they can run again.
+benchmarkclean:
+	rm -f $(SCRIPTS_BENCH)
+
 nolog:
 	-rm -f test.log test_result.log messages
 
diff --git a/src/version.c b/src/version.c
index cc3542a..999cfde 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5031,
+/**/
     5030,
 /**/
     5029,