cmd/link: do not pass -Bsymbolic for PE DLLs

This is only a valid option on ELF. Binutils accepts it, but LLVM
rejects it, so for Windows, it's best to just omit it.

Updates #44250.
Updates #39326.
Updates #38755.
Updates #36439.
Updates #43800.

Change-Id: Iffd2345d757f23dd737e63bd464cd412527077c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/291632
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

Author: zx2c4

src/cmd/link/internal/ld/lib.go

@@ -1343,8 +1343,6 @@ func (ctxt *Link) hostlink() {
 		if ctxt.HeadType == objabi.Hdarwin {
 			argv = append(argv, "-dynamiclib")
 		} else {
-			// ELF.
-			argv = append(argv, "-Wl,-Bsymbolic")
 			if ctxt.UseRelro() {
 				argv = append(argv, "-Wl,-z,relro")
 			}
@@ -1357,6 +1355,8 @@ func (ctxt *Link) hostlink() {
 				// Pass -z nodelete to mark the shared library as
 				// non-closeable: a dlclose will do nothing.
 				argv = append(argv, "-Wl,-z,nodelete")
+				// Only pass Bsymbolic on non-Windows.
+				argv = append(argv, "-Wl,-Bsymbolic")
 			}
 		}
 	case BuildModeShared: