build: separate compiler and libs

compiler/internal/lib/runtime/zgoos_darwin.go

@@ -0,0 +1,24 @@
+//go:build !ios && darwin
+
+package runtime
+
+const GOOS = `darwin`
+
+const IsAix = 0
+const IsAndroid = 0
+const IsDarwin = 1
+const IsDragonfly = 0
+const IsFreebsd = 0
+const IsHurd = 0
+const IsIllumos = 0
+const IsIos = 0
+const IsJs = 0
+const IsLinux = 0
+const IsNacl = 0
+const IsNetbsd = 0
+const IsOpenbsd = 0
+const IsPlan9 = 0
+const IsSolaris = 0
+const IsWasip1 = 0
+const IsWindows = 0
+const IsZos = 0