Filter Spectrum sources for each component

At long last, changing one file somewhere won't cause every Spectrum
component to be rebuilt unnecessarily.

Signed-off-by: Alyssa Ross <hi@alyssa.is>

1 files changed, 4 insertions, 1 deletions

diff --git a/host/initramfs/default.nix b/host/initramfs/default.nix
index f290595..2ff613e 100644
--- a/host/initramfs/default.nix
+++ b/host/initramfs/default.nix
@@ -80,7 +80,10 @@ stdenvNoCC.mkDerivation {
 
   src = lib.fileset.toSource {
     root = ../..;
-    fileset = src;
+    fileset = lib.fileset.intersection src (lib.fileset.unions [
+      ./.
+      ../../lib/common.mk
+    ]);
   };
   sourceRoot = "source/host/initramfs";