std.process.Child: use clone3 on arm and arm64

Author: ruihe774

lib/std/os/linux/aarch64.zig

@@ -133,6 +133,25 @@ pub fn clone() callconv(.Naked) usize {
     );
 }
 
+pub fn clone3() callconv(.Naked) usize {
+    asm volatile (
+        \\      mov x8,#435 // SYS_clone3
+        \\      svc #0
+        \\
+        \\      cbz x0,1f
+        \\      ret
+        \\
+        \\1:    .cfi_undefined lr
+        \\      mov fp, 0
+        \\      mov lr, 0
+        \\
+        \\      mov x0,x3
+        \\      blr x2
+        \\      mov x8,#93 // SYS_exit
+        \\      svc #0
+    );
+}
+
 pub const restore = restore_rt;
 
 pub fn restore_rt() callconv(.Naked) noreturn {

lib/std/os/linux/arm.zig

@@ -134,6 +134,26 @@ pub fn clone() callconv(.Naked) usize {
     );
 }
 
+pub fn clone3() callconv(.Naked) usize {
+    asm volatile (
+        \\    stmfd sp!,{r7}
+        \\    mov r7,#435 // SYS_clone3
+        \\    svc 0
+        \\    tst r0,r0
+        \\    beq 1f
+        \\    ldmfd sp!,{r7}
+        \\    bx lr
+        \\
+        \\    // https://github.com/llvm/llvm-project/issues/115891
+        \\1:  mov r11, #0
+        \\    mov lr, #0
+        \\    mov r0,r3
+        \\    bx r2
+        \\    mov r7,#1 // SYS_exit
+        \\    svc 0
+    );
+}
+
 pub fn restore() callconv(.Naked) noreturn {
     switch (@import("builtin").zig_backend) {
         .stage2_c => asm volatile (