app: merge app/internal/wm into package app

The app and app/internal/wm packages are tightly coupled, requiring
quite a bit of forwarding types, values and constants from the internal
package to export it. Further, no other package imports package wm.

This change merges the two packages.

While here, drop the pre-Go 1.14 SIGPIPE workaround.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/metal_ios.go

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+//go:build !nometal
+// +build !nometal
+
+package app
+
+/*
+#cgo CFLAGS: -Werror -xobjective-c -fmodules -fobjc-arc
+
+@import UIKit;
+
+@import QuartzCore.CAMetalLayer;
+
+#include <CoreFoundation/CoreFoundation.h>
+
+Class gio_layerClass(void) {
+	return [CAMetalLayer class];
+}
+
+static CFTypeRef getMetalLayer(CFTypeRef viewRef) {
+	@autoreleasepool {
+		UIView *view = (__bridge UIView *)viewRef;
+		return CFBridgingRetain(view.layer);
+	}
+}
+
+static void resizeDrawable(CFTypeRef viewRef, CFTypeRef layerRef) {
+	@autoreleasepool {
+		UIView *view = (__bridge UIView *)viewRef;
+		CAMetalLayer *layer = (__bridge CAMetalLayer *)layerRef;
+		layer.contentsScale = view.contentScaleFactor;
+		CGSize size = layer.bounds.size;
+		size.width *= layer.contentsScale;
+		size.height *= layer.contentsScale;
+		layer.drawableSize = size;
+	}
+}
+*/
+import "C"
+
+func getMetalLayer(view C.CFTypeRef) C.CFTypeRef {
+	return C.getMetalLayer(view)
+}
+
+func resizeDrawable(view, layer C.CFTypeRef) {
+	C.resizeDrawable(view, layer)
+}