os: treat Getwd result of EINVAL/ERANGE the same as ENAMETOOLONG

At least Darwin and OpenBSD seem to return EINVAL if the resulting
name would be too long. Solaris seems to return ERANGE.

Fixes golang#69233
Fixes golang#69234

Change-Id: I9b51d41461e9576c633bf2fc0e96ca3e4d986255
Reviewed-on: https://go-review.googlesource.com/c/go/+/609579
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>

src/os/error_errno.go

@@ -11,3 +11,4 @@ import "syscall"
 type syscallErrorType = syscall.Errno
 
 const errENOSYS = syscall.ENOSYS
+const errERANGE = syscall.ERANGE

src/os/error_plan9.go

@@ -9,3 +9,4 @@ import "syscall"
 type syscallErrorType = syscall.ErrorString
 
 var errENOSYS = syscall.NewError("function not implemented")
+var errERANGE = syscall.NewError("out of range")

src/os/getwd.go

@@ -59,7 +59,10 @@ func Getwd() (dir string, err error) {
 				break
 			}
 		}
-		if err != syscall.ENAMETOOLONG {
+		// Linux returns ENAMETOOLONG if the result is too long.
+		// BSD systems appear to return EINVAL.
+		// Solaris appears to use ERANGE.
+		if err != syscall.ENAMETOOLONG && err != syscall.EINVAL && err != errERANGE {
 			return dir, NewSyscallError("getwd", err)
 		}
 	}