legal-info: allow to declare the actual sources for binary packages

The FOO_SITE/FOO_SOURCE variables usually point to a tarball containing
source code.

For the downloaded external toolchains this is not true, the "source"
tarball actually contains binaries. This is fine for making Buildroot
work, but for legal-info we really want to ship real source code, not
binaries.

Luckily, some (hopefully all) toolchain vendors publish a downloadable
tarball containing the source code counterpart for their binary
packages.

Here we allow the user to declare the URL of this other tarball in the
pair of variables FOO_ACTUAL_SOURCE_TARBALL (by default equal to
FOO_SOURCE) and FOO_ACTUAL_SOURCE_SITE (by default equal to FOO_SITE).
If the "actual source" package can be downloaded from the same
directory as the binary package, then only FOO_ACTUAL_SOURCE_TARBALL
needs to be set.

Note this change is not strictly toolchain-specific: it might be useful
for other packages that happen to ship binaries in the same way.

[Thomas:
  - remove "the source code has not been saved" warning that could
    never be triggered due to how the conditions were
    organized. Discussed with Luca live during the meeting.]

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Makefile

@@ -647,7 +647,6 @@ legal-info-prepare: $(LEGAL_INFO_DIR)
 	@$(call legal-manifest,PACKAGE,VERSION,LICENSE,LICENSE FILES,SOURCE ARCHIVE,SOURCE SITE,HOST)
 	@$(call legal-manifest,buildroot,$(BR2_VERSION_FULL),GPLv2+,COPYING,not saved,not saved,HOST)
 	@$(call legal-warning,the Buildroot source code has not been saved)
-	@$(call legal-warning,the toolchain has not been saved)
 	@cp $(BR2_CONFIG) $(LEGAL_INFO_DIR)/buildroot.config
 
 legal-info: dirs legal-info-clean legal-info-prepare $(foreach p,$(PACKAGES),$(p)-all-legal-info) \

package/pkg-generic.mk

@@ -708,12 +708,18 @@ ifneq ($$($(2)_SITE_METHOD),local)
 ifneq ($$($(2)_SITE_METHOD),override)
 # Packages that have a tarball need it downloaded beforehand
 $(1)-legal-info: $(1)-source $$(REDIST_SOURCES_DIR_$$(call UPPERCASE,$(4)))
-$(2)_MANIFEST_TARBALL = $$($(2)_SOURCE)
-$(2)_MANIFEST_SITE = $$(call qstrip,$$($(2)_SITE))
 endif
 endif
 endif
 
+# If FOO_ACTUAL_SOURCE_TARBALL is explicitly defined, it means FOO_SOURCE is
+# indeed a binary (e.g. external toolchain) and FOO_ACTUAL_SOURCE_TARBALL/_SITE
+# point to the actual sources tarball. Use the actual sources for legal-info.
+# For most packages the FOO_SITE/FOO_SOURCE pair points to real source code,
+# so these are the defaults for FOO_ACTUAL_*.
+$(2)_ACTUAL_SOURCE_TARBALL ?= $$($(2)_SOURCE)
+$(2)_ACTUAL_SOURCE_SITE    ?= $$(call qstrip,$$($(2)_SITE))
+
 # legal-info: produce legally relevant info.
 $(1)-legal-info:
 # Packages without a source are assumed to be part of Buildroot, skip them.
@@ -744,13 +750,16 @@ else
 # Other packages
 
 ifeq ($$($(2)_REDISTRIBUTE),YES)
+ifneq ($$($(2)_ACTUAL_SOURCE_TARBALL),$$($(2)_SOURCE))
+	$(call DOWNLOAD,$$($(2)_ACTUAL_SOURCE_SITE)/$$($(2)_ACTUAL_SOURCE_TARBALL))
+endif
 # Copy the source tarball (just hardlink if possible)
-	@cp -l $$(DL_DIR)/$$($(2)_SOURCE) $$(REDIST_SOURCES_DIR_$$(call UPPERCASE,$(4))) 2>/dev/null || \
-	   cp $$(DL_DIR)/$$($(2)_SOURCE) $$(REDIST_SOURCES_DIR_$$(call UPPERCASE,$(4)))
+	@cp -l $$(DL_DIR)/$$($(2)_ACTUAL_SOURCE_TARBALL) $$(REDIST_SOURCES_DIR_$$(call UPPERCASE,$(4))) 2>/dev/null || \
+	    cp $$(DL_DIR)/$$($(2)_ACTUAL_SOURCE_TARBALL) $$(REDIST_SOURCES_DIR_$$(call UPPERCASE,$(4)))
 endif # redistribute
 
 endif # other packages
-	@$$(call legal-manifest,$$($(2)_RAWNAME),$$($(2)_VERSION),$$($(2)_LICENSE),$$($(2)_MANIFEST_LICENSE_FILES),$$($(2)_MANIFEST_TARBALL),$$($(2)_MANIFEST_SITE),$$(call UPPERCASE,$(4)))
+	@$$(call legal-manifest,$$($(2)_RAWNAME),$$($(2)_VERSION),$$($(2)_LICENSE),$$($(2)_MANIFEST_LICENSE_FILES),$$($(2)_ACTUAL_SOURCE_TARBALL),$$($(2)_ACTUAL_SOURCE_SITE),$$(call UPPERCASE,$(4)))
 endif # ifneq ($$(call qstrip,$$($(2)_SOURCE)),)
 	$$(foreach hook,$$($(2)_POST_LEGAL_INFO_HOOKS),$$(call $$(hook))$$(sep))