[Buildroot] [PATCH 2/8] core/pkg-utils: add a macro to pretty-print a help entry

[Yann E. MORIN]

To ensure that all the help entries we display are all formatted the
same, we currently indent the help texts manually.

Also, when a br2-external tree wants to display local custom help, they
have to rely on a hard-coded layout (if they want to match our iwn
output, which is not mandatory).

Add a macro to pretty-print make rules in the help texts.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Jérôme Pouiller <jezz at sysmic.org>
Cc: Arnout Vandecappelle <arnout at mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
---
 package/pkg-utils.mk | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/package/pkg-utils.mk b/package/pkg-utils.mk
index f88313a..873dbec 100644
--- a/package/pkg-utils.mk
+++ b/package/pkg-utils.mk
@@ -104,6 +104,19 @@ define sep
 
 endef
 
+# Pretty-print a make rule in the help text
+#
+# $(1): a list of double- or single-quoted string representing the rule
+#       and their help text, formatted as:  "action : help for action"
+#       'action' should be less than 22 characters, otherwise the help
+#       text will not be correctly indented.
+#
+define HELP_RULE
+	for h in $(1); do \
+		printf "  %-22s - %s\n" "$${h%% : *}" "$${h#* : }"; \
+	done
+endef
+
 # check-deprecated-variable -- throw an error on deprecated variables
 # example:
 #   $(eval $(call check-deprecated-variable,FOO_MAKE_OPT,FOO_MAKE_OPTS))
-- 
1.9.1