internal/lockedfile: fix build constraints on solaris

The version of this file in the main repo uses a "!unix" build
constraint, which had to be ported to a longer list for inclusion in
gopls (which still supports Go versions that predate the "unix" tag).

Solaris is a Unix derivative, and its implementation is provided in
the "fcntl" implementation.

Updates golang/go#57747.

Change-Id: Ibde8ce55dadc03ad3cb797b5320f5b75580f639f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/463776
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
diff --git a/internal/lockedfile/internal/filelock/filelock_other.go b/internal/lockedfile/internal/filelock/filelock_other.go
index a108915..cde868f 100644
--- a/internal/lockedfile/internal/filelock/filelock_other.go
+++ b/internal/lockedfile/internal/filelock/filelock_other.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !(aix || darwin || dragonfly || freebsd || illumos || linux || netbsd || openbsd) && !plan9 && !windows
-// +build !aix,!darwin,!dragonfly,!freebsd,!illumos,!linux,!netbsd,!openbsd,!plan9,!windows
+//go:build !(aix || darwin || dragonfly || freebsd || illumos || linux || netbsd || openbsd || solaris) && !plan9 && !windows
+// +build !aix,!darwin,!dragonfly,!freebsd,!illumos,!linux,!netbsd,!openbsd,!solaris,!plan9,!windows
 
 package filelock