downloads: add basic CVS support

The support is for pserver mode anonymous CVS.
source-check is based on login since many servers don't support or have
ls/rls disabled.

Usage is pretty straightforward.
PKG_SITE defines the site hostname and remote directory.
The module is defined by the bare package name.
Version is date based.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
diff --git a/Config.in b/Config.in
index 65c29b4..1b30ce1 100644
--- a/Config.in
+++ b/Config.in
@@ -42,6 +42,10 @@
 	string "Git command"
 	default "git"
 
+config BR2_CVS
+	string "CVS command"
+	default "cvs"
+
 config BR2_LOCALFILES
 	string "Local files retrieval command"
 	default "cp"