package/go: adjust comments

Adjust comments in the Go package to improve clarity:

Config.in.host:

 - Add comment mentioning list of supported architectures.

go.mk:

 - Reword comment re: copying src/ to host/
   - the previously linked issue is not relevant.
   - instead: mention that src/ is needed for stdlib.
 - Adjust comment re: adjusting file timestamps.
   - mention this is needed to avoid rebuilding stdlib

Signed-off-by: Christian Stewart <christian@aperture.us>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/go/Config.in.host

@@ -3,6 +3,8 @@ config BR2_PACKAGE_HOST_GO_TARGET_ARCH_SUPPORTS
 	bool
 	default y
 	depends on BR2_PACKAGE_HOST_GO_BOOTSTRAP_STAGE2_ARCH_SUPPORTS
+	# See https://go.dev/doc/install/source#environment
+	# See src/go/build/syslist.go for the list of supported architectures
 	depends on (BR2_arm && BR2_TOOLCHAIN_SUPPORTS_PIE) || BR2_aarch64 \
 		|| BR2_i386 || BR2_x86_64 || BR2_powerpc64le \
 		|| BR2_mips64 || BR2_mips64el || BR2_riscv || BR2_s390x

package/go/go.mk

@@ -154,12 +154,11 @@ define HOST_GO_INSTALL_CMDS
 	cp -a $(@D)/pkg/include $(@D)/pkg/linux_* $(HOST_GO_ROOT)/pkg/
 	cp -a $(@D)/pkg/tool $(HOST_GO_ROOT)/pkg/
 
-	# There is a known issue which requires the go sources to be installed
-	# https://golang.org/issue/2775
+	# The Go sources must be installed to the host/ tree for the Go stdlib.
 	cp -a $(@D)/src $(HOST_GO_ROOT)/
 
-	# Set all file timestamps to prevent the go compiler from rebuilding any
-	# built in packages when programs are built.
+	# Set file timestamps to prevent the Go compiler from rebuilding the stdlib
+	# when compiling other programs.
 	find $(HOST_GO_ROOT) -type f -exec touch -r $(@D)/bin/go {} \;
 endef