change prepare worker to use fork instead of threads (#1685)

Co-authored-by: Marcin S <marcin@realemail.net>

Cargo.lock

@@ -8627,6 +8627,17 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "nix"
+version = "0.27.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2eb04e9c688eff1c89d72b407f168cf79bb9e867a9d3323ed6c01519eb9cc053"
+dependencies = [
+ "bitflags 2.4.0",
+ "cfg-if",
+ "libc",
+]
+
 [[package]]
 name = "no-std-net"
 version = "0.6.0"
@@ -9103,6 +9114,16 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "os_pipe"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ae859aa07428ca9a929b936690f8b12dc5f11dd8c6992a18ca93919f28bc177"
+dependencies = [
+ "libc",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "os_str_bytes"
 version = "6.5.1"
@@ -12525,6 +12546,9 @@ name = "polkadot-node-core-pvf-execute-worker"
 version = "1.0.0"
 dependencies = [
  "cpu-time",
+ "libc",
+ "nix 0.27.1",
+ "os_pipe",
  "parity-scale-codec",
  "polkadot-node-core-pvf-common",
  "polkadot-parachain-primitives",
@@ -12539,6 +12563,8 @@ dependencies = [
  "cfg-if",
  "criterion 0.4.0",
  "libc",
+ "nix 0.27.1",
+ "os_pipe",
  "parity-scale-codec",
  "polkadot-node-core-pvf-common",
  "polkadot-primitives",