[source] include/download.mk: Allow specify DownloadMethod specific options

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/b9aab34eb4ddf935ee6296f587857e5a495cae0e

commit b9aab34eb4ddf935ee6296f587857e5a495cae0e
Author: Florian Fainelli <f.fainelli at gmail.com>
AuthorDate: Wed Nov 9 09:34:17 2016 -0800

    include/download.mk: Allow specify DownloadMethod specific options
    
    This is going to be used to migrate the hand rolled git clone for the kernel
    into using the git download method. The kernel uses custom options that we may
    have to pass down.
    
    Signed-off-by: Florian Fainelli <f.fainelli at gmail.com>
---
 include/download.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/download.mk b/include/download.mk
index 2797e90..9fbc3fb 100644
--- a/include/download.mk
+++ b/include/download.mk
@@ -93,7 +93,7 @@ define DownloadMethod/git
 		cd $(TMP_DIR)/dl && \
 		rm -rf $(SUBDIR) && \
 		[ \! -d $(SUBDIR) ] && \
-		git clone $(URL) $(SUBDIR) && \
+		git clone $(OPTS) $(URL) $(SUBDIR) && \
 		(cd $(SUBDIR) && git checkout $(VERSION) && \
 		git submodule update --init --recursive) && \
 		echo "Packing checkout..." && \
@@ -172,6 +172,7 @@ define Download/Defaults
   MIRROR:=1
   MIRROR_MD5SUM:=x
   VERSION:=
+  OPTS:=
 endef
 
 define Download