cmd/link/internal/ld: disable execute-only for external linking on openbsd/arm64

The Go arm64 assembler places constants into the text section of a binary.
OpenBSD 7.3 enabled xonly by default on OpenBSD/arm64. This means that any
externally linked Go binary now segfaults. Disable execute-only when invoking
the external linker on openbsd/arm64, in order to work around this issue.

Updates #59615

Change-Id: I1a291293da3c6e4409b21873d066ea15e9bfe280
Reviewed-on: https://go-review.googlesource.com/c/go/+/484555
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Reviewed-by: Aaron Bieber <[email protected]>
Run-TryBot: Joel Sing <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>

Author: 4a6f656c

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

@@ -1407,6 +1407,12 @@ func (ctxt *Link) hostlink() {
 	case objabi.Hopenbsd:
 		argv = append(argv, "-Wl,-nopie")
 		argv = append(argv, "-pthread")
+		if ctxt.Arch.InFamily(sys.ARM64) {
+			// Disable execute-only on openbsd/arm64 - the Go arm64 assembler
+			// currently stores constants in the text section rather than in rodata.
+			// See issue #59615.
+			argv = append(argv, "-Wl,--no-execute-only")
+		}
 	case objabi.Hwindows:
 		if windowsgui {
 			argv = append(argv, "-mwindows")