cmd/go: add -Wl,--export-dynamic to linker flag whitelist

Fixes #27496

Change-Id: I53538c7697729294a9e50ace26a6a7183131e837
Reviewed-on: https://go-review.googlesource.com/134016
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

src/cmd/go/internal/work/security.go

@@ -170,6 +170,7 @@ var validLinkerFlags = []*regexp.Regexp{
 	re(`-Wl,-e[=,][a-zA-Z0-9]*`),
 	re(`-Wl,--enable-new-dtags`),
 	re(`-Wl,--end-group`),
+	re(`-Wl,--(no-)?export-dynamic`),
 	re(`-Wl,-framework,[^,@\-][^,]+`),
 	re(`-Wl,-headerpad_max_install_names`),
 	re(`-Wl,--no-undefined`),