Add vendored bc-decaf as input

flake.lock

@@ -21,6 +21,22 @@
         "url": "https://gitlab.linphone.org/BC/public/bcunit"
       }
     },
+    "decaf-source": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1658325219,
+        "narHash": "sha256-QFOAgLiPbG2ZdwKoCOrVD5/sPq9IH4rtAWnnk/rZWcs=",
+        "ref": "refs/heads/bc",
+        "rev": "876ddb4d465c94f97beba1be450e8538d866cc5d",
+        "revCount": 561,
+        "type": "git",
+        "url": "https://gitlab.linphone.org/BC/public/external/decaf"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://gitlab.linphone.org/BC/public/external/decaf"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1662096612,
@@ -38,6 +54,7 @@
     "root": {
       "inputs": {
         "bcunit": "bcunit",
+        "decaf-source": "decaf-source",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -6,9 +6,13 @@
       url = git+https://gitlab.linphone.org/BC/public/bcunit?ref=feature/nix-flake;
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    decaf-source = {
+      url = git+https://gitlab.linphone.org/BC/public/external/decaf;
+      flake = false;
+    };
   };
 
-  outputs = { self, nixpkgs, bcunit, ... }: {
+  outputs = { self, nixpkgs, bcunit, decaf-source, ... }: {
 
     overlays.default = final: prev: {
 
@@ -16,6 +20,10 @@
         version = "dev";
         src = ./.;
       });
+      bc-decaf = prev.bc-decaf.overrideAttrs (attrs: {
+        version = "dev";
+        src = decaf-source;
+      });
 
     };