syscall.Getpagesize(): add test, implement for Linux and Windows

src/os/getpagesize_test.go

@@ -0,0 +1,17 @@
+//go:build windows || darwin || (linux && !baremetal)
+// +build windows darwin linux,!baremetal
+
+package os_test
+
+import (
+	"os"
+	"testing"
+)
+
+func TestGetpagesize(t *testing.T) {
+	pagesize := os.Getpagesize()
+	if pagesize == 0x1000 || pagesize == 0x4000 || pagesize == 0x10000 {
+		return
+	}
+	t.Errorf("os.Getpagesize() returns strange value %d", pagesize)
+}

src/os/types_anyos.go

@@ -7,6 +7,11 @@
 
 package os
 
+import "syscall"
+
+// Getpagesize returns the underlying system's memory page size.
+func Getpagesize() int { return syscall.Getpagesize() }
+
 func (fs *fileStat) Name() string { return fs.name }
 func (fs *fileStat) IsDir() bool  { return fs.Mode().IsDir() }