[Buildroot] [RFCv3 07/15] package/pkg-generic: handle host-tar as an extract dependency

[Thomas Petazzoni]

This moves the host-tar dependency handling from
DEPENDENCY_HOST_PREREQ to an extract dependency.

To achieve that, check-host-tar.mk fills in the
BR2_TAR_HOST_DEPENDENCY with host-tar if building a host-tar is
needed. The name BR2_TAR_HOST_DEPENDENCY has been chosen because it
matches the name BR2_CMAKE_HOST_DEPENDENCY already used in
check-host-cmake.mk.

The BR2_TAR_HOST_DEPENDENCY is added to all packages, except host-tar
itself (obviously) and host-skeleton, because we depend on
host-skeleton to install host-tar properly in HOST_DIR.

In addition, we modify tar.mk to explicitly build host-tar without
ccache: since ccache source code is available as a tarball, ccache
will obviously depend on host-tar if the system tar is insufficient.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
---
Changes since v2:
 - New patch
---
 package/pkg-generic.mk                 | 4 ++++
 package/tar/tar.mk                     | 6 ++++++
 support/dependencies/check-host-tar.mk | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
index 824c34bec9..86dd2561d4 100644
--- a/package/pkg-generic.mk
+++ b/package/pkg-generic.mk
@@ -587,6 +587,10 @@ ifneq ($(1),host-skeleton)
 $(2)_DEPENDENCIES += host-skeleton
 endif
 
+ifeq ($(filter host-tar host-skeleton,$(1)),)
+$(2)_EXTRACT_DEPENDENCIES += $(BR2_TAR_HOST_DEPENDENCY)
+endif
+
 # Eliminate duplicates in dependencies
 $(2)_FINAL_DEPENDENCIES = $$(sort $$($(2)_DEPENDENCIES))
 $(2)_FINAL_EXTRACT_DEPENDENCIES = $$(sort $$($(2)_EXTRACT_DEPENDENCIES))
diff --git a/package/tar/tar.mk b/package/tar/tar.mk
index cb2ddc0eca..813eabed14 100644
--- a/package/tar/tar.mk
+++ b/package/tar/tar.mk
@@ -44,4 +44,10 @@ define HOST_TAR_EXTRACT_CMDS
 	mv $(@D)/tar-$(TAR_VERSION)/* $(@D)
 	rmdir $(@D)/tar-$(TAR_VERSION)
 endef
+
+# we are built before ccache
+HOST_TAR_CONF_ENV = \
+	CC="$(HOSTCC_NOCCACHE)" \
+	CXX="$(HOSTCXX_NOCCACHE)"
+
 $(eval $(host-autotools-package))
diff --git a/support/dependencies/check-host-tar.mk b/support/dependencies/check-host-tar.mk
index ad0b32e277..d07f727c4c 100644
--- a/support/dependencies/check-host-tar.mk
+++ b/support/dependencies/check-host-tar.mk
@@ -1,6 +1,6 @@
 TAR ?= tar
 
 ifeq (,$(call suitable-host-package,tar,$(TAR)))
-DEPENDENCIES_HOST_PREREQ += host-tar
 TAR = $(HOST_DIR)/bin/tar
+BR2_TAR_HOST_DEPENDENCY += host-tar
 endif
-- 
2.13.6