darwin does not have PATH_MAX

Define our own, with the value from Linux.

daemonize.go

@@ -29,7 +29,7 @@ func exitOnUsr1() {
 func forkChild() int {
 	name := os.Args[0]
 	// Use the full path to our executable if we can get if from /proc.
-	buf := make([]byte, syscall.PathMax)
+	buf := make([]byte, syscallcompat.PATH_MAX)
 	n, err := syscall.Readlink("/proc/self/exe", buf)
 	if err == nil {
 		name = string(buf[:n])

internal/fusefrontend_reverse/rfs.go

@@ -333,8 +333,7 @@ func (rfs *ReverseFS) Readlink(relPath string, context *fuse.Context) (string, f
 	cTarget := rfs.nameTransform.B64.EncodeToString(cBinTarget)
 	// The kernel will reject a symlink target above 4096 chars and return
 	// and I/O error to the user. Better emit the proper error ourselves.
-	const PATH_MAX = 4096 // not defined on Darwin
-	if len(cTarget) > PATH_MAX {
+	if len(cTarget) > syscallcompat.PATH_MAX {
 		return "", fuse.Status(syscall.ENAMETOOLONG)
 	}
 	return cTarget, fuse.OK

internal/syscallcompat/sys_common.go

@@ -6,6 +6,8 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+const PATH_MAX = 4096 // not defined on Darwin
+
 // Readlinkat exists both in Linux and in MacOS 10.10+. We may add an
 // emulated version for users on older MacOS versions if there is
 // demand.