[Buildroot] [PATCH 2/6] pkg-generic: add check_shlibs_deps hooks

["Jérôme Pouiller" <jezz@sysmic.org>]

Call check-shlibs-deps after each package. Errors reported by this hooks mean
the package could compile differently depending of build order (= missing
optional dependency).

Currently, missed dependencies are only logged to
`$(BUILD_DIR)/missing-dependencies.txt'. In future, we may remove `-w' in order
to make these errors fatal.

In order to get correct results from step_check_shlibs_deps, we need to compute
recursive dependencies for package. get_recursive_dependencies is brittle, don't
try to add spaces or line breaks inside its definition.

A good idea to find many missed optional dependencies would be to use this
script with LTP. Unfortunately, check-shlibs-deps does not (yet) work with it.

Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
---
 package/pkg-generic.mk | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
index 827de62..987efa6 100644
--- a/package/pkg-generic.mk
+++ b/package/pkg-generic.mk
@@ -110,6 +110,26 @@ define step_check_build_dir
 endef
 GLOBAL_INSTRUMENTATION_HOOKS += step_check_build_dir
 
+# Compute dependencies for a set of packages recursively
+# $(1): list of package to check
+# $(2): list of package already processed. Only used for internal recursion.
+#     Keep empty for normal usage.
+# Example usage:
+#     $(call get_recursive_dependencies,util-linux,)
+define get_recursive_dependencies
+$(sort $(foreach d,$(1),$(if $(filter $(d),$(2)),$(d),$(call get_recursive_dependencies,$(d) $($(call UPPERCASE,$(d))_DEPENDENCIES),$(d) $(2)))))
+endef
+
+define step_check_shlibs_deps
+	$(if $(filter install-target,$(2)),\
+		$(if $(filter end,$(1)),support/scripts/check-shlibs-deps \
+			-b $(CONFIG_DIR) -p $(3) -w \
+			-d $(subst $(space),$(comma),$(call get_recursive_dependencies,$(3),)) \
+			| tee -a $(BUILD_DIR)/missing-dependencies.txt
+		))
+endef
+GLOBAL_INSTRUMENTATION_HOOKS += step_check_shlibs_deps
+
 # User-supplied script
 ifneq ($(BR2_INSTRUMENTATION_SCRIPTS),)
 define step_user
-- 
2.9.3