blueprint: add kernel name customization

Blueprints can now be used to specify a kernel as part of the kernel
customizations.  Specifying a kernel adds it to the package list.

If no known kernel is specified (neither in the customizations nor the
package list), the default "kernel" is included automatically.

If kernels are specified in both the package list and the
customizations, both are added (even if they're duplicates).

internal/blueprint/blueprint.go

@@ -103,6 +103,14 @@ func (b *Blueprint) GetPackages() []string {
 	for _, group := range b.Groups {
 		packages = append(packages, "@"+group.Name)
 	}
+
+	if kc := b.Customizations.GetKernel(); kc != nil && kc.Name != "" {
+		kpkg := Package{Name: b.Customizations.Kernel.Name}
+		packages = append(packages, kpkg.ToNameVersion())
+	} else { // no Kernel specified; add default
+		kpkg := Package{Name: "kernel"}
+		packages = append(packages, kpkg.ToNameVersion())
+	}
 	return packages
 }
 

internal/blueprint/customizations.go

@@ -13,6 +13,7 @@ type Customizations struct {
 }
 
 type KernelCustomization struct {
+	Name   string `json:"name,omitempty" toml:"name,omitempty"`
 	Append string `json:"append" toml:"append"`
 }