version up: babeld hmac-nxd1

The gitclone reciped is used for babeld to get submodules added in
the latest babeld version.
gcc is forced to use `-std=gnu99` because default std has changed
in version 5.1 and we get errors when compiling babeld with older gcc.

component/babeld/buildout.cfg

 [buildout]
 parts = babeld
 
+[babeld-repository]
+recipe = slapos.recipe.build:gitclone
+repository = https://lab.nexedi.com/nexedi/babeld.git
+branch = master
+git-executable = ${git:location}/bin/git
+revision = hmac-nxd1
+
 [babeld]
 recipe = slapos.recipe.cmmi
-url = https://lab.nexedi.com/nexedi/babeld/repository/archive.tar.gz?ref=v1.8.4-nxd1
-md5sum = 536cca6abe34eb9faeda8682b80ee7bc
+path = ${babeld-repository:location}
+make-options = CC='gcc -std=gnu99'
 configure-command =
   echo "No configure.."