Enable library evolution for SwiftPM build

Author: make1986

Package.swift

@@ -24,7 +24,11 @@ let package = Package(
                 .product(name: "PlainPocketFFT", package: "plain-pocketfft"),
                 .product(name: "PocketFFT", package: "pocketfft")
             ],
-            path: "Sources"
+            path: "Sources",
+            swiftSettings: [
+                .unsafeFlags(["-enable-library-evolution"]),
+                .define("BUILD_LIBRARY_FOR_DISTRIBUTION")
+            ]
         ),
         .testTarget(
             name: "OtosakuFeatureExtractorTests",

Sources/OtosakuFeatureExtractor/Array+Extensions.swift

@@ -9,8 +9,8 @@
 import Foundation
 import Accelerate
 
-import PocketFFT
-import PlainPocketFFT
+internal import PocketFFT
+internal import PlainPocketFFT
 import CoreGraphics
 
 extension FloatingPoint {