cmd/link: add flag help to go doc via internal/flagdoc

The 'go doc cmd/link' command showed incomplete flag help compared to 'go tool link -h'. This change adds a new internal package flagdoc with duplicated flag variables so that 'go doc' displays full help without build conflicts. Fixes #72086

Author: Mehrbod2002

src/cmd/link/internal/flagdoc/flagdoc.go

@@ -0,0 +1,64 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package flagdoc contains flag definitions for 'go doc cmd/link'.
+// It duplicates flags from internal/ld/main.go to show full help.
+package flagdoc
+
+import (
+"cmd/internal/quoted"
+"flag"
+)
+
+var (
+// === LINKER FLAGS FOR go doc cmd/link ===
+// Duplicated from cmd/link/internal/ld/main.go
+Buildid = flag.String("buildid", "", "record `id` as Go toolchain build id")
+BindNow = flag.Bool("bindnow", false, "mark a dynamically linked ELF object for immediate function binding")
+Outfile = flag.String("o", "", "write output to `file`")
+PluginPath = flag.String("pluginpath", "", "full path name for plugin")
+Fipso = flag.String("fipso", "", "write fips module to `file`")
+InstallSuffix = flag.String("installsuffix", "", "set package directory `suffix`")
+DumpDep = flag.Bool("dumpdep", false, "dump symbol dependency graph")
+Race = flag.Bool("race", false, "enable race detector")
+Msan = flag.Bool("msan", false, "enable MSan interface")
+Asan = flag.Bool("asan", false, "enable ASan interface")
+Aslr = flag.Bool("aslr", true, "enable ASLR for buildmode=c-shared on windows")
+FieldTrack = flag.String("k", "", "set field tracking `symbol`")
+LibGCC = flag.String("libgcc", "", "compiler support lib for internal linking; use \"none\" to disable")
+Tmpdir = flag.String("tmpdir", "", "use `directory` for temporary files")
+Extld = new(quoted.Flag)
+Extldflags = new(quoted.Flag)
+Extar = flag.String("extar", "", "archive program for buildmode=c-archive")
+CaptureHostObjs = flag.String("capturehostobjs", "", "capture host object files loaded during internal linking to specified dir")
+Aflag = flag.Bool("a", false, "no-op (deprecated)")
+Cflag = flag.Bool("c", false, "dump call graph")
+Dflag = flag.Bool("d", false, "disable dynamic executable")
+Fflag = flag.Bool("f", false, "ignore version mismatch")
+Gflag = flag.Bool("g", false, "disable go package data checks")
+Hflag = flag.Bool("h", false, "halt on error")
+Nflag = flag.Bool("n", false, "no-op (deprecated)")
+Sflag = flag.Bool("s", false, "disable symbol table")
+HostBuildid = flag.String("B", "", "set ELF NT_GNU_BUILD_ID `note` or Mach-O UUID; use \"gobuildid\" to generate it from the Go build ID; \"none\" to disable")
+Interpreter = flag.String("I", "", "use `linker` as ELF dynamic linker")
+CheckLinkname = flag.Bool("checklinkname", true, "check linkname symbol references")
+DebugTramp = flag.Int("debugtramp", 0, "debug trampolines")
+DebugTextSize = flag.Int("debugtextsize", 0, "debug text section max size")
+DebugNosplit = flag.Bool("debugnosplit", false, "dump nosplit call graph")
+StrictDups = flag.Int("strictdups", 0, "sanity check duplicate symbol contents during object file reading (1=warn 2=err).")
+Round = flag.Int64("R", -1, "set address rounding `quantum`")
+TextAddr = flag.Int64("T", -1, "set the start address of text symbols")
+DataAddr = flag.Int64("D", -1, "set the start address of data symbols")
+FuncAlign = flag.Int("funcalign", 0, "set function align to `N` bytes")
+EntrySymbol = flag.String("E", "", "set `entry` symbol name")
+PruneWeakMap = flag.Bool("pruneweakmap", true, "prune weak mapinit refs")
+RandLayout = flag.Int64("randlayout", 0, "randomize function layout")
+AllErrors = flag.Bool("e", false, "no limit on number of errors reported")
+CpuProfile = flag.String("cpuprofile", "", "write cpu profile to `file`")
+MemProfile = flag.String("memprofile", "", "write memory profile to `file`")
+MemProfileRate = flag.Int64("memprofilerate", 0, "set runtime.MemProfileRate to `rate`")
+Benchmark = flag.String("benchmark", "", "set to 'mem' or 'cpu' to enable phase benchmarking")
+BenchmarkProfile = flag.String("benchmarkprofile", "", "emit phase profiles to `base`_phase.{cpu,mem}prof")
+Wflag = new(bool)
+)