newt: Add possibility to use generated linker script

Now if "bsp.linkerscript" has value "autogenerated", default linker script
will be passed to the linker.

newt/pkg/bsp_package.go

@@ -82,6 +82,16 @@ func (bsp *BspPackage) resolvePathSetting(
 	return path, nil
 }
 
+func (bsp *BspPackage) getAutogeneratedLinkerScriptPath() (string, error) {
+	defaultLinkerScriptPath := "bin/" + bsp.yov.Pkg.Name() + "/generated/link/mynewt.ld"
+	proj := interfaces.GetProject()
+	path, err := proj.ResolvePath(proj.Path(), defaultLinkerScriptPath)
+	if err != nil {
+		return "", err
+	}
+	return path, nil
+}
+
 // Interprets a setting as either a single linker script or a list of linker
 // scripts.
 func (bsp *BspPackage) resolveLinkerScriptSetting(
@@ -103,14 +113,28 @@ func (bsp *BspPackage) resolveLinkerScriptSetting(
 			return nil, err
 		}
 
-		if path != "" {
+		if path == "autogenerated" {
+			path, err = bsp.getAutogeneratedLinkerScriptPath()
+			if err != nil {
+				return nil, util.PreNewtError(err,
+					"Could not resolve autogenerated linker script path for target \"%s\"",
+					bsp.yov.Pkg.Name())
+			}
+			paths = append(paths, path)
+		} else if path != "" {
 			paths = append(paths, path)
 		}
 	} else {
 		proj := interfaces.GetProject()
 
 		// Read each linker script from the list.
 		for _, val := range vals {
+			if val == "autogenerated" {
+				return nil, util.PreNewtError(err,
+					"Both autogenerated and custom linker scripts cannot be used."+
+						"Newt handles either autogenerated linker script or a list of custom linker scripts.")
+			}
+
 			path, err := proj.ResolvePath(ypkg.Repo().Path(), val)
 			if err != nil {
 				return nil, util.PreNewtError(err,
@@ -226,7 +250,6 @@ func NewBspPackage(lpkg *LocalPackage, yov *BspYCfgOverride) (*BspPackage, error
 	lpkg.Load()
 	bsp.LocalPackage = lpkg
 	bsp.BspV = ycfg.NewYCfg(bsp.BspYamlPath())
-
 	err := bsp.Reload(nil)
 
 	return bsp, err