feat: allow modular kernel config snippets

Author: 0x416e746f6e

kernel/mkosi.build

@@ -15,9 +15,20 @@ if [[ -n "${KERNEL_CONFIG_SNIPPETS:-}" ]]; then
     IFS=',' read -ra snippets <<< "$KERNEL_CONFIG_SNIPPETS"
     for snippet in "${snippets[@]}"; do
         snippet_file="$SRCDIR/$snippet"
-        [[ -f "$snippet_file" ]] && cat "$snippet_file" >> "$config_file"
+        if [[ -f "$snippet_file" ]]; then
+            cat "$snippet_file" >> "$config_file" || true
+        fi
     done
 fi
+for snippets_var in "${!KERNEL_CONFIG_SNIPPETS_@}"; do
+    IFS=',' read -ra snippets <<< "${!snippets_var}"
+    for snippet in "${snippets[@]}"; do
+        snippet_file="$SRCDIR/$snippet"
+        if [[ -f "$snippet_file" ]]; then
+            cat "$snippet_file" >> "$config_file" || true
+        fi
+    done
+done
 
 # Calculate cache key and paths
 config_hash=$(sha256sum "$config_file" | cut -d' ' -f1 | cut -c1-12)
@@ -43,6 +54,9 @@ else
     mkosi-chroot --chdir "/build/kernel-${KERNEL_VERSION}" make olddefconfig
     mkosi-chroot --chdir "/build/kernel-${KERNEL_VERSION}" make -j "$(nproc 2>/dev/null || echo 2)" bzImage ARCH=x86_64 CONFIG_EFI_STUB=y
 
+    echo "# kernel config:"
+    mkosi-chroot --chdir "/build/kernel-${KERNEL_VERSION}" cat .config
+
     # Cache result
     mkdir -p "$cache_dir"
     cp arch/x86_64/boot/bzImage "$cache_dir/"