[Buildroot] [PATCH v2 1/2] help: add a way to document targets declared in local.mk/external.mk

[Jérôme Pouiller]

It is handy to use local.mk or external.mk to add specific targets
for current project. However, until now, it not possible to add help
message these targets.
This patch add EXTRA_HELP variable. This variable is aimed to be assigned
from any .mk files. Its content is displayed with 'make help'.

For exemple:
  EXTRA_HELP += "flash                  - Flash target"
  EXTRA_HELP += "chroot                 - Chroot into target/"
  EXTRA_HELP += "qemu                   - Run image with qemu"
  EXTRA_HELP += "install-nfs            - Extract rootfs in \$$NFSROOT (=$(NFSROOT))"
  EXTRA_HELP += "`printf '%-22s%s' '$(var)-feature' ' - Call $(var) feature'`"
  EXTRA_HELP += "Please contact support at company.com in case of problem."

Signed-off-by: Jérôme Pouiller <jezz at sysmic.org>
---
v2:
  - Rename LOCAL_HELP to EXTRA_HELP
  - Remove introduction lines (so, 'ifneq ($(LOCAL_HELP),)' is no more needed)

 Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile b/Makefile
index f2822a2..1c9f63c 100644
--- a/Makefile
+++ b/Makefile
@@ -948,6 +948,7 @@ ifeq ($(BR2_TARGET_BAREBOX),y)
 	@echo '  barebox-menuconfig     - Run barebox menuconfig'
 	@echo '  barebox-savedefconfig  - Run barebox savedefconfig'
 endif
+	@for i in $(EXTRA_HELP); do echo "  $$i"; done
 	@echo
 	@echo 'Documentation:'
 	@echo '  manual                 - build manual in all formats'
-- 
2.7.0