doc/install/gccgo: note gold linker deprecation

The gold linker is deprecated as of GNU Binutils 2.44 (February 2025)
and may be removed in future releases. Update the documentation to:

- Add a deprecation notice at the start of the Gold section
- Recommend lld as an alternative that supports split stacks
- Note that gold is now in a separate binutils-with-gold tarball
- Provide the --with-ld flag for using lld

Fixes golang/go#71923

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Change-Id: Ieeeb217ef858af08d2e7b70e0ecaaed3457466f8
Reviewed-on: https://go-review.googlesource.com/c/website/+/741421
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

_content/doc/install/gccgo.html

diff --git a/_content/doc/install/gccgo.html b/_content/doc/install/gccgo.html
index 21080d9..18a144e 100644
--- a/_content/doc/install/gccgo.html
+++ b/_content/doc/install/gccgo.html
@@ -135,12 +135,25 @@
 <h3 id="Gold">Gold</h3>
 
 <p>
+<b>Note:</b> The gold linker is deprecated as of GNU Binutils 2.44 (February 2025)
+and may be removed in future releases. Consider using
+<a href="https://lld.llvm.org/">lld</a> (LLVM's linker) as an alternative,
+which also supports split stacks on x86_64.
+</p>
+
+<p>
 On x86 GNU/Linux systems the gccgo compiler is able to
 use a small discontiguous stack for goroutines. This permits programs
 to run many more goroutines, since each goroutine can use a relatively
-small stack. Doing this requires using the gold linker version 2.22
-or later. You can either install GNU binutils 2.22 or later, or you
-can build gold yourself.
+small stack. Doing this requires using a linker that supports split stacks.
+The gold linker version 2.22 or later supports this feature,
+as does lld.
+</p>
+
+<p>
+If you still need to use gold, you can either install GNU binutils 2.22 or later
+(note: as of binutils 2.44, gold is in a separate binutils-with-gold tarball),
+or you can build gold yourself.
 </p>
 
 <p>
@@ -164,6 +177,7 @@
 <p>
 However you install gold, when you configure gccgo, use the
 option <code>--with-ld=<var>GOLD_BINARY</var></code>.
+Similarly, for lld use <code>--with-ld=/path/to/ld.lld</code>.
 </p>
 
 <h3 id="Prerequisites">Prerequisites</h3>