doc/next: add tentative DWARF 5 release note fragment

Add a small fragment describing the move to DWARF 5 for this release,
along with the name of the GOEXPERIMENT.

Updates #26379.

Change-Id: I3a30a71436133e2e0a5edf1ba0db84b9cc17cc5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/657176
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/doc/next/5-toolchain.md b/doc/next/5-toolchain.md
index 0f4a816479754c2c55ce9ead3ac3581bb1f4453c..971fa39608e35249354be26431c1a27675ad78ef 100644 (file)
--- a/doc/next/5-toolchain.md
+++ b/doc/next/5-toolchain.md
@@ -1,7 +1,15 @@
 ## Compiler {#compiler}
 
+<!-- https://go.dev/issue/26379 -->
+
+The compiler and linker in Go 1.25 now generate debug information
+using [DWARF version 5](https://dwarfstd.org/dwarf5std.html); the
+newer DWARF version reduces the space required for debuging
+information in Go binaries.
+DWARF 5 generation is gated by the "dwarf5" GOEXPERIMENT; this
+functionality can be disabled (for now) using GOEXPERIMENT=nodwarf5.
+
 ## Assembler {#assembler}
 
 ## Linker {#linker}
 
-