build: ipkg: new field Alternatives

It's a list of specs of the following form seprated by commas to
describe alternatives provided by this package

    <prio>:<path>:<altpath>

<path> will be a symbolic link to <altpath> of the highest <prio>

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

diff --git a/include/package-ipkg.mk b/include/package-ipkg.mk
index 620be991b3e3e1ab95ae9df8d6fb25384cec66de..bf508fb4934ad6df4893e18745ab47fd93de6ed8 100644 (file)
--- a/include/package-ipkg.mk
+++ b/include/package-ipkg.mk
@@ -159,6 +159,7 @@ Version: $(VERSION)
 $$(call addfield,Depends,$$(Package/$(1)/DEPENDS)
 )$$(call addfield,Conflicts,$$(call mergelist,$(CONFLICTS))
 )$$(call addfield,Provides,$$(call mergelist,$(PROVIDES))
+)$$(call addfield,Alternatives,$$(call mergelist,$(ALTERNATIVES))
 )$$(call addfield,Source,$(SOURCE)
 )$$(call addfield,License,$$(PKG_LICENSE)
 )$$(call addfield,LicenseFiles,$$(PKG_LICENSE_FILES)