[source] build: ipkg: new field Alternatives

[LEDE Commits]

yousong pushed a commit to source.git, branch master:
https://git.lede-project.org/73bc636aba3ec0c6381605d1f11088955101975a

commit 73bc636aba3ec0c6381605d1f11088955101975a
Author: Yousong Zhou <yszhou4tech at gmail.com>
AuthorDate: Sun Mar 5 16:19:46 2017 +0800

    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 at gmail.com>
---
 include/package-ipkg.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/package-ipkg.mk b/include/package-ipkg.mk
index 620be99..bf508fb 100644
--- 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)