hsavmcore: Avoid recompilation of overlay during install step

overlay.o was being recompiled during the install step because
it depended on the target check-dep-fuse which is phony and,
therefore, always outdated. The solution is to create an empty file
for the target check-dep-fuse after its successful completion. This
prevents make from rebuilding overlay.o during installation.

Closes: https://github.com/ibm-s390-linux/s390-tools/pull/118
Fixes: 5a7d2a58c8 ("hsavmcore: Fix fuse dependency checking")
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Suggested-by: Ingo Franzki <ifranzki@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

hsavmcore/Makefile

@@ -69,6 +69,7 @@ check-dep-fuse:
 		"fuse.h", \
 		"fuse-devel or libfuse-dev", \
 		"HAVE_FUSE=0")
+	touch check-dep-fuse
 
 install: all
 	$(INSTALL) -g $(GROUP) -o $(OWNER) -m 755 hsavmcore \
@@ -81,6 +82,6 @@ install: all
 endif # HAVE_FUSE
 
 clean:
-	rm -f hsavmcore $(objects)
+	rm -f hsavmcore $(objects) check-dep-fuse
 
 .PHONY: all install clean