newt: Add constant syscfg for each package

Now every package included in build will add
syscfg PKG_<pkg.name> and set it to 1.
This config can be used to conditionally include
other configs or packages if some package is included.

Author: m-gorecki

newt/resolve/resolve.go

@@ -601,6 +601,7 @@ func (r *Resolver) reloadCfg() (bool, error) {
 
 	cfg.AddInjectedSettings()
 	cfg.ResolveValueRefs()
+	cfg.AddPkgNamesSettings(lpkgs)
 
 	// Determine if any new settings have been added or if any existing
 	// settings have changed.

newt/syscfg/marshal.go

@@ -33,6 +33,7 @@ var cfgSettingNameTypeMap = map[string]CfgSettingType{
 
 var cfgSettingNameStateMap = map[string]CfgSettingState{
 	"good":         CFG_SETTING_STATE_GOOD,
+	"const":        CFG_SETTING_STATE_CONST,
 	"deprecated":   CFG_SETTING_STATE_DEPRECATED,
 	"defunct":      CFG_SETTING_STATE_DEFUNCT,
 	"experimental": CFG_SETTING_STATE_EXPERIMENTAL,

newt/syscfg/syscfg.go

@@ -242,6 +242,22 @@ func (cfg *Cfg) AddInjectedSettings() {
 	}
 }
 
+func (cfg *Cfg) AddPkgNamesSettings(pkgs []*pkg.LocalPackage) {
+	for _, pkg := range pkgs {
+		entry := CfgEntry{
+			Name:       "PKG_" + pkg.Name(),
+			PackageDef: pkg,
+			State:      CFG_SETTING_STATE_CONST,
+			Value:      "1",
+			History: []CfgPoint{{
+				Value:  "1",
+				Source: pkg,
+			}},
+		}
+		cfg.Settings[entry.Name] = entry
+	}
+}
+
 func (cfg *Cfg) ResolveValueRefs() {
 	for k, entry := range cfg.Settings {
 		refName, val, err := cfg.ExpandRef(strings.TrimSpace(entry.Value))