Add static_libs field to target.vendor

test: builds with a local Android.bp that uses target.vender.static_libs

Change-Id: Id1b70660ccab26025c280497916929d303d16aff
diff --git a/cc/linker.go b/cc/linker.go
index 61ae757..07d41ec 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -101,6 +101,10 @@
 			// variant of the C/C++ module.
 			Shared_libs []string
 
+			// list of static libs that only should be used to build the vendor
+			// variant of the C/C++ module.
+			Static_libs []string
+
 			// list of shared libs that should not be used to build the vendor variant
 			// of the C/C++ module.
 			Exclude_shared_libs []string
@@ -204,6 +208,7 @@
 		deps.SharedLibs = append(deps.SharedLibs, linker.Properties.Target.Vendor.Shared_libs...)
 		deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Vendor.Exclude_shared_libs)
 		deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Vendor.Exclude_shared_libs)
+		deps.StaticLibs = append(deps.StaticLibs, linker.Properties.Target.Vendor.Static_libs...)
 		deps.StaticLibs = removeListFromList(deps.StaticLibs, linker.Properties.Target.Vendor.Exclude_static_libs)
 		deps.HeaderLibs = removeListFromList(deps.HeaderLibs, linker.Properties.Target.Vendor.Exclude_header_libs)
 		deps.ReexportStaticLibHeaders = removeListFromList(deps.ReexportStaticLibHeaders, linker.Properties.Target.Vendor.Exclude_static_libs)