Allow check-exapmles to work with our make, upstream's syntax is
gmake-only...

--- Examples/Makefile.in	2018-05-23 14:35:06
+++ Examples/Makefile.in	2018-07-10 23:06:07
@@ -657,6 +657,6 @@
 
 
-%.check:
-	$(MAKE) -C $* check-examples
+${SUBDIR_CHECKS}:
+	$(MAKE) -C ${@:.check=} check-examples
 
 .PHONY: examples check-examples $(SUBDIRS)