diff --git a/cutekit/__init__.py b/cutekit/__init__.py
index 0d7c996..efb0d7f 100644
--- a/cutekit/__init__.py
+++ b/cutekit/__init__.py
@@ -55,7 +55,8 @@ def setupLogger(verbose: bool):
 def main() -> int:
     try:
         shell.mkdir(const.GLOBAL_CK_DIR)
-        args = cli.parse(sys.argv[1:])
+        extraArgs = os.environ.get("CK_EXTRA_ARGS", None)
+        args = cli.parse((extraArgs.split(" ") if extraArgs else []) + sys.argv[1:])
         setupLogger(args.consumeOpt("verbose", False) is True)
 
         const.setup()
diff --git a/cutekit/builder.py b/cutekit/builder.py
index a6cd2d8..b26cfdd 100644
--- a/cutekit/builder.py
+++ b/cutekit/builder.py
@@ -66,7 +66,7 @@ class ProductScope(ComponentScope):
 
 # --- Variables -------------------------------------------------------------- #
 
-Compute = Callable[[TargetScope], str]
+Compute = Callable[[TargetScope], list[str]]
 _vars: dict[str, Compute] = {}
 
 
@@ -79,21 +79,21 @@ def var(name: str) -> Callable[[Compute], Compute]:
 
 
 @var("builddir")
-def _computeBuilddir(scope: TargetScope) -> str:
+def _computeBuilddir(scope: TargetScope) -> list[str]:
     """
     This variable is needed by ninja to know where to put
     the .ninja_log file.
     """
-    return scope.target.builddir
+    return [scope.target.builddir]
 
 
 @var("hashid")
-def _computeHashid(scope: TargetScope) -> str:
-    return scope.target.hashid
+def _computeHashid(scope: TargetScope) -> list[str]:
+    return [scope.target.hashid]
 
 
 @var("cincs")
-def _computeCinc(scope: TargetScope) -> str:
+def _computeCinc(scope: TargetScope) -> list[str]:
     res = set()
 
     for c in scope.registry.iterEnabled(scope.target):
@@ -104,11 +104,11 @@ def _computeCinc(scope: TargetScope) -> str:
         elif c.type == model.Kind.LIB:
             res.add(str(Path(c.dirname()).parent))
 
-    return " ".join(sorted(map(lambda i: f"-I{i}", res)))
+    return sorted(map(lambda i: f"-I{i}", res))
 
 
 @var("cdefs")
-def _computeCdef(scope: TargetScope) -> str:
+def _computeCdef(scope: TargetScope) -> list[str]:
     res = set()
 
     def sanatize(s: str) -> str:
@@ -125,7 +125,7 @@ def _computeCdef(scope: TargetScope) -> str:
             res.add(f"-D__ck_{sanatize(k)}_{sanatize(str(v))}__")
             res.add(f"-D__ck_{sanatize(k)}_value={str(v)}")
 
-    return " ".join(sorted(res))
+    return sorted(res)
 
 
 def buildpath(scope: ComponentScope, path) -> Path:
@@ -272,15 +272,27 @@ def all(w: ninja.Writer, scope: TargetScope) -> list[str]:
     return all
 
 
+def applyExtraProps(scope: TargetScope, name: str, var: list[str]) -> list[str]:
+    target: model.Target = scope.target
+    extra = target.props.get(f"ck-{name}-extra", None)
+    if extra:
+        var += extra.split(" ")
+    override = target.props.get(f"ck-{name}-override")
+    if override:
+        var = override.split(" ")
+    return var
+
+
 def gen(out: TextIO, scope: TargetScope):
     w = ninja.Writer(out)
+    target: model.Target = scope.target
 
     w.comment("File generated by the build system, do not edit")
     w.newline()
 
     w.separator("Variables")
     for name, compute in _vars.items():
-        w.variable(name, compute(scope))
+        w.variable(name, applyExtraProps(scope, name, compute(scope)))
     w.newline()
 
     w.separator("Tools")
@@ -289,7 +301,10 @@ def gen(out: TextIO, scope: TargetScope):
         tool = scope.target.tools[i]
         rule = rules.rules[i]
         w.variable(i, tool.cmd)
-        w.variable(i + "flags", " ".join(rule.args + tool.args))
+        w.variable(
+            i + "flags",
+            " ".join(applyExtraProps(scope, i + "flags", rule.args + tool.args)),
+        )
         w.rule(
             i,
             f"{tool.cmd} {(tool.rule or rule.rule).replace('$flags',f'${i}flags')}",
diff --git a/meta/nix/flake.lock b/meta/nix/flake.lock
index 03d15a1..37b3fba 100644
--- a/meta/nix/flake.lock
+++ b/meta/nix/flake.lock
@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1705774713,
-        "narHash": "sha256-j6ADaDH9XiumUzkTPlFyCBcoWYhO83lfgiSqEJF2zcs=",
+        "lastModified": 1706098335,
+        "narHash": "sha256-r3dWjT8P9/Ah5m5ul4WqIWD8muj5F+/gbCdjiNVBKmU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "1b64fc1287991a9cce717a01c1973ef86cb1af0b",
+        "rev": "a77ab169a83a4175169d78684ddd2e54486ac651",
         "type": "github"
       },
       "original": {
diff --git a/meta/nix/flake.nix b/meta/nix/flake.nix
index 40d1e96..b8f7854 100644
--- a/meta/nix/flake.nix
+++ b/meta/nix/flake.nix
@@ -25,8 +25,12 @@
             graphviz
           ];
         };
-      in {
+      in
+      {
         package.ck = ck;
         defaultPackage = self.package.${system}.ck;
+        devShell = pkgs.mkShell {
+          buildInputs = [ ck ];
+        };
       });
 }