[release-branch.go1.20] runtime: skip darwin osinit_hack on ios

Darwin needs the osinit_hack call to fix some bugs in the Apple libc
that surface when Go programs call exec. On iOS, the functions that
osinit_hack uses are not available, so signing fails. But on iOS exec
is also unavailable, so the hack is not needed. Disable it there,
which makes signing work again.

Fixes golang#58323.
Fixes golang#58419.

Change-Id: I3f1472f852bb36c06854fe1f14aa27ad450c5945
Reviewed-on: https://go-review.googlesource.com/c/go/+/466516
Run-TryBot: Russ Cox <[email protected]>
Reviewed-by: Dave Anderson <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Russ Cox <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
Reviewed-on: https://go-review.googlesource.com/c/go/+/467316

Author: rsc

src/runtime/sys_darwin.go

@@ -213,7 +213,9 @@ func pthread_kill_trampoline()
 //
 //go:nosplit
 func osinit_hack() {
-	libcCall(unsafe.Pointer(abi.FuncPCABI0(osinit_hack_trampoline)), nil)
+	if GOOS == "darwin" { // not ios
+		libcCall(unsafe.Pointer(abi.FuncPCABI0(osinit_hack_trampoline)), nil)
+	}
 	return
 }
 func osinit_hack_trampoline()