Start work on a SHM implementation in Go

tools/utils/shm/shm_openbsd.go

@@ -0,0 +1,40 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package shm
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+var _ = fmt.Print
+
+const SHM_DIR = "/tmp"
+
+func create_temp(pattern string) (*os.File, error) {
+	ans, err := os.CreateTemp(SHM_DIR, pattern)
+	if err != nil {
+		return nil, err
+	}
+	return ans, nil
+}
+
+func Open(name string) (*os.File, error) {
+	if !filepath.IsAbs(name) {
+		name = filepath.Join(SHM_DIR, name)
+	}
+	ans, err := os.OpenFile(name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	return ans, nil
+}
+
+func Unlink(name string) error {
+	if !filepath.IsAbs(name) {
+		name = filepath.Join(SHM_DIR, name)
+	}
+	return os.Remove(name)
+
+}