Makefile: List fuzz targets in 'make help'

List softmmu fuzz targets in 'make help' output:

  $ make help
  ...
  Architecture specific targets:
  aarch64-softmmu/all            - Build for aarch64-softmmu
  aarch64-softmmu/fuzz           - Build fuzzer for aarch64-softmmu
  alpha-softmmu/all              - Build for alpha-softmmu
  alpha-softmmu/fuzz             - Build fuzzer for alpha-softmmu
  arm-softmmu/all                - Build for arm-softmmu
  arm-softmmu/fuzz               - Build fuzzer for arm-softmmu
  ...

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200514143433.18569-3-philmd@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Makefile

@@ -1252,7 +1252,11 @@ endif
 	@$(if $(TARGET_DIRS), \
 		echo 'Architecture specific targets:'; \
 		$(foreach t, $(TARGET_DIRS), \
-		$(call print-help-run,$(t)/all,Build for $(t));) \
+		$(call print-help-run,$(t)/all,Build for $(t)); \
+		$(if $(CONFIG_FUZZ), \
+			$(if $(findstring softmmu,$(t)), \
+				$(call print-help-run,$(t)/fuzz,Build fuzzer for $(t)); \
+		))) \
 		echo '')
 	@$(if $(TOOLS), \
 		echo 'Tools targets:'; \