package/go-bootstrap-stage3: add stage3 for go1.22 support

Add a third bootstrap stage with Go1.21.x necessary for go1.22 bootstrap.

go-bootstrap-stage1 is Go1.4.x, the final version to support bootstrap using a C
compiler (later versions require the Go compiler for bootstrapping).

See: https://go.dev/doc/install/source#bootstrapFromSource

go-bootstrap-stage2 is Go 1.19.13, the last version to support bootstrap using
the Go1.4.x compiler.

go-bootstrap-stage3 is Go 1.21.8, the last version to support bootstrap using
the Go1.19.13 compiler. Go 1.20 requires a minimum of go 1.17.13 to bootstrap.

See: https://go.dev/doc/go1.20#bootstrap

This patch is in preparation for bumping the host-go package to >go1.22.x, which
requires a minimum of Go1.20.x for bootstrap.

See: https://go.dev/doc/go1.22#bootstrap

Signed-off-by: Christian Stewart <christian@aperture.us>
[Arnout: add GOCACHE definition]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

DEVELOPERS

@@ -596,6 +596,7 @@ F:	package/fuse-overlayfs/
 F:	package/go/
 F:	package/go-bootstrap-stage1/
 F:	package/go-bootstrap-stage2/
+F:	package/go-bootstrap-stage3/
 F:	package/gocryptfs/
 F:	package/mbpfan/
 F:	package/moby-buildkit/

package/Config.in.host

@@ -46,6 +46,7 @@ menu "Host utilities"
 	source "package/go/Config.in.host"
 	source "package/go-bootstrap-stage1/Config.in.host"
 	source "package/go-bootstrap-stage2/Config.in.host"
+	source "package/go-bootstrap-stage3/Config.in.host"
 	source "package/google-breakpad/Config.in.host"
 	source "package/gptfdisk/Config.in.host"
 	source "package/imagemagick/Config.in.host"

package/go-bootstrap-stage3/Config.in.host

@@ -0,0 +1,4 @@
+config BR2_PACKAGE_HOST_GO_BOOTSTRAP_STAGE3_ARCH_SUPPORTS
+	bool
+	default y
+	depends on BR2_PACKAGE_HOST_GO_BOOTSTRAP_STAGE2_ARCH_SUPPORTS

package/go-bootstrap-stage3/go-bootstrap-stage3.hash

@@ -0,0 +1,3 @@
+# From https://go.dev/dl
+sha256  dc806cf75a87e1414b5b4c3dcb9dd3e9cc98f4cfccec42b7af617d5a658a3c43  go1.21.8.src.tar.gz
+sha256  2d36597f7117c38b006835ae7f537487207d8ec407aa9d9980794b2030cbc067  LICENSE

package/go-bootstrap-stage3/go-bootstrap-stage3.mk

@@ -0,0 +1,54 @@
+################################################################################
+#
+# go-bootstrap-stage3
+#
+################################################################################
+
+# Use last Go version that go-bootstrap-stage2 can build: v1.21.x
+# See https://go.dev/doc/go1.22#bootstrap
+GO_BOOTSTRAP_STAGE3_VERSION = 1.21.8
+GO_BOOTSTRAP_STAGE3_SITE = https://storage.googleapis.com/golang
+GO_BOOTSTRAP_STAGE3_SOURCE = go$(GO_BOOTSTRAP_STAGE3_VERSION).src.tar.gz
+
+GO_BOOTSTRAP_STAGE3_LICENSE = BSD-3-Clause
+GO_BOOTSTRAP_STAGE3_LICENSE_FILES = LICENSE
+
+# Use go-bootstrap-stage2 to bootstrap.
+HOST_GO_BOOTSTRAP_STAGE3_DEPENDENCIES = host-go-bootstrap-stage2
+
+HOST_GO_BOOTSTRAP_STAGE3_ROOT = $(HOST_DIR)/lib/go-$(GO_BOOTSTRAP_STAGE3_VERSION)
+
+# The go build system is not compatible with ccache, so use
+# HOSTCC_NOCCACHE.  See https://github.com/golang/go/issues/11685.
+HOST_GO_BOOTSTRAP_STAGE3_MAKE_ENV = \
+	GO111MODULE=off \
+	GOCACHE=$(HOST_GO_HOST_CACHE) \
+	GOROOT_BOOTSTRAP=$(HOST_GO_BOOTSTRAP_STAGE2_ROOT) \
+	GOROOT_FINAL=$(HOST_GO_BOOTSTRAP_STAGE3_ROOT) \
+	GOROOT="$(@D)" \
+	GOBIN="$(@D)/bin" \
+	GOOS=linux \
+	CC=$(HOSTCC_NOCCACHE) \
+	CXX=$(HOSTCXX_NOCCACHE) \
+	CGO_ENABLED=0
+
+define HOST_GO_BOOTSTRAP_STAGE3_BUILD_CMDS
+	cd $(@D)/src && \
+		$(HOST_GO_BOOTSTRAP_STAGE3_MAKE_ENV) ./make.bash $(if $(VERBOSE),-v)
+endef
+
+define HOST_GO_BOOTSTRAP_STAGE3_INSTALL_CMDS
+	$(INSTALL) -D -m 0755 $(@D)/bin/go $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/bin/go
+	$(INSTALL) -D -m 0755 $(@D)/bin/gofmt $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/bin/gofmt
+
+	cp -a $(@D)/lib $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/
+
+	mkdir -p $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/pkg
+	cp -a $(@D)/pkg/include $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/pkg/
+	cp -a $(@D)/pkg/tool $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/pkg/
+
+	# The Go sources must be installed to the host/ tree for the Go stdlib.
+	cp -a $(@D)/src $(HOST_GO_BOOTSTRAP_STAGE3_ROOT)/
+endef
+
+$(eval $(host-generic-package))