mac: drop build support for swift versions earlier than version 4.1

this drops support for swift <4.1 and with this support for xcode <=9.2.
this was the last setup that is officially working on macOS 10.12.

our old legacy build macOS 10.12 + xcode 9.2 is replaced by macOS 10.13
+ xcode 9.4.1 with swift 4.1. the macOS 10.13 + xcode 10.1 VM is
replaced by the latest macOS 10.14 + xcode 11.3.1 VM. this is the oldest
version officially supported by Apple.

this is in preparations for the following commit.

1 files changed, 0 insertions, 27 deletions

diff --git a/osdep/macos/swift_compat.swift b/osdep/macos/swift_compat.swift
index c14aa08282..24c00b0ae1 100644
--- a/osdep/macos/swift_compat.swift
+++ b/osdep/macos/swift_compat.swift
@@ -33,7 +33,6 @@ extension String {
 #endif
 
 extension NSPasteboard.PasteboardType {
-
     static let fileURLCompat: NSPasteboard.PasteboardType = {
         if #available(OSX 10.13, *) {
             return .fileURL
@@ -53,7 +52,6 @@ extension NSPasteboard.PasteboardType {
 
 #if !swift(>=5.0)
 extension Data {
-
     mutating func withUnsafeMutableBytes<Type>(_ body: (UnsafeMutableRawBufferPointer) throws -> Type) rethrows -> Type {
         let dataCount = count
         return try withUnsafeMutableBytes { (ptr: UnsafeMutablePointer<UInt8>) throws -> Type in
@@ -65,33 +63,8 @@ extension Data {
 
 #if !swift(>=4.2)
 extension NSDraggingInfo {
-
     var draggingPasteboard: NSPasteboard {
         get { return draggingPasteboard() }
     }
 }
 #endif
-
-#if !swift(>=4.1)
-extension Array {
-
-    func compactMap<ElementOfResult>(_ transform: (Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] {
-        return try self.flatMap(transform)
-    }
-}
-
-extension Array where Element == [CGLPixelFormatAttribute] {
-
-    func contains(_ obj: [CGLPixelFormatAttribute]) -> Bool {
-        return self.contains(where:{ $0 == obj })
-    }
-}
-
-extension NSWindow.Level {
-
-    static func +(left: NSWindow.Level, right: Int) -> NSWindow.Level {
-        return NSWindow.Level(left.rawValue + right)
-    }
-}
-#endif
-