plugin: add support for dragonfly/amd64

Author: tuxillo

src/cmd/dist/test.go

@@ -1663,7 +1663,7 @@ func buildModeSupported(compiler, buildmode, goos, goarch string) bool {
 		case "linux/amd64", "linux/arm", "linux/arm64", "linux/386", "linux/loong64", "linux/s390x", "linux/ppc64le",
 			"android/amd64", "android/386",
 			"darwin/amd64", "darwin/arm64",
-			"freebsd/amd64":
+			"freebsd/amd64", "dragonfly/amd64":
 			return true
 		}
 		return false

src/internal/platform/supported.go

@@ -211,7 +211,7 @@ func BuildModeSupported(compiler, buildmode, goos, goarch string) bool {
 		case "linux/amd64", "linux/arm", "linux/arm64", "linux/386", "linux/loong64", "linux/s390x", "linux/ppc64le",
 			"android/amd64", "android/386",
 			"darwin/amd64", "darwin/arm64",
-			"freebsd/amd64":
+			"freebsd/amd64", "dragonfly/amd64":
 			return true
 		}
 		return false

src/plugin/plugin.go

@@ -25,8 +25,8 @@
 // However, the plugin mechanism has many significant drawbacks that
 // should be considered carefully during the design. For example:
 //
-//   - Plugins are currently supported only on Linux, FreeBSD, and
-//     macOS, making them unsuitable for applications intended to be
+//   - Plugins are currently supported only on Linux, FreeBSD, DragonFly BSD
+//     and macOS, making them unsuitable for applications intended to be
 //     portable.
 //
 //   - Plugins are poorly supported by the Go race detector. Even simple

src/plugin/plugin_dlopen.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (linux && cgo) || (darwin && cgo) || (freebsd && cgo)
+//go:build (linux && cgo) || (darwin && cgo) || (freebsd && cgo) || (dragonfly && cgo)
 
 package plugin
 

src/plugin/plugin_stubs.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!linux && !freebsd && !darwin) || !cgo
+//go:build (!linux && !freebsd && !darwin && !dragonfly) || !cgo
 
 package plugin