Build now working with new rust

Apply missing patches from master and work around an issue in
compiler_builtins

patches/rust.patch

@@ -1,3 +1,15 @@
+diff --git a/Cargo.toml b/Cargo.toml
+index 5dd315ef2f7..680fb821c4c 100644
+--- a/Cargo.toml
++++ b/Cargo.toml
+@@ -120,6 +120,7 @@ strip = true
+ rustc-std-workspace-core = { path = 'library/rustc-std-workspace-core' }
+ rustc-std-workspace-alloc = { path = 'library/rustc-std-workspace-alloc' }
+ rustc-std-workspace-std = { path = 'library/rustc-std-workspace-std' }
++compiler_builtins = { git = "https://github.com/rust-lang/compiler-builtins", rev = "0.1.105" }
+
+ [patch."https://github.com/rust-lang/rust-clippy"]
+ clippy_lints = { path = "src/tools/clippy/clippy_lints" }
 diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
 index 941d767b..1b4004c4 100644
 --- a/compiler/rustc_target/src/spec/mod.rs
@@ -10,6 +22,21 @@ index 941d767b..1b4004c4 100644
      ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
      ("riscv32im-risc0-zkvm-elf", riscv32im_risc0_zkvm_elf),
      ("riscv32im-unknown-none-elf", riscv32im_unknown_none_elf),
+diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
+index 5ed6b357e20..a31645ab6e7 100644
+--- a/src/bootstrap/src/lib.rs
++++ b/src/bootstrap/src/lib.rs
+@@ -91,6 +91,10 @@
+     /* Extra values not defined in the built-in targets yet, but used in std */
+     (Some(Mode::Std), "target_env", Some(&["libnx", "p2"])),
+     // (Some(Mode::Std), "target_os", Some(&[])),
++    // #[cfg(bootstrap)] zkvm
++    (Some(Mode::Std), "target_os", Some(&["zkvm"])),
++    // #[cfg(bootstrap)] athena
++    (Some(Mode::Std), "target_vendor", Some(&["athena", "succinct"])),
+     (Some(Mode::Std), "target_arch", Some(&["arm64ec", "spirv", "nvptx", "xtensa"])),
+     /* Extra names used by dependencies */
+     // FIXME: Used by serde_json, but we should not be triggering on external dependencies.
 diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
 index eab9138b..60507063 100644
 --- a/src/tools/build-manifest/src/main.rs
@@ -18,7 +45,7 @@ index eab9138b..60507063 100644
      "powerpc-unknown-linux-gnu",
      "powerpc64-unknown-linux-gnu",
      "powerpc64le-unknown-linux-gnu",
-+    "riscv32e-athena-zkvm-elf",
++    "riscv32em-athena-zkvm-elf",
      "riscv32i-unknown-none-elf",
      "riscv32im-risc0-zkvm-elf",
      "riscv32im-unknown-none-elf",
@@ -72,3 +99,58 @@ index 00000000..a84f76c2
 +    }
 +}
 +
+diff --git a/library/std/src/sys/pal/zkvm/args.rs b/library/std/src/sys/pal/zkvm/args.rs
+index 7753cf63840..583c16e3a47 100644
+--- a/library/std/src/sys/pal/zkvm/args.rs
++++ b/library/std/src/sys/pal/zkvm/args.rs
+@@ -1,6 +1,7 @@
+ use super::{abi, WORD_SIZE};
+ use crate::ffi::OsString;
+ use crate::fmt;
++use crate::sys::os_str;
+ use crate::sys_common::FromInner;
+
+ pub struct Args {
+@@ -33,7 +34,7 @@ fn argv(i: usize) -> OsString {
+         // "os_str".
+         let arg_bytes: &[u8] =
+             unsafe { crate::slice::from_raw_parts(words.cast() as *const u8, arg_len) };
+-        OsString::from_inner(super::os_str::Buf { inner: arg_bytes.to_vec() })
++        OsString::from_inner(os_str::Buf { inner: arg_bytes.to_vec() })
+     }
+ }
+
+diff --git a/library/std/src/sys/pal/zkvm/mod.rs b/library/std/src/sys/pal/zkvm/mod.rs
+index 228a976dbab..c5a1843d5ff 100644
+--- a/library/std/src/sys/pal/zkvm/mod.rs
++++ b/library/std/src/sys/pal/zkvm/mod.rs
+@@ -12,8 +12,6 @@
+ pub mod alloc;
+ #[path = "../zkvm/args.rs"]
+ pub mod args;
+-#[path = "../unix/cmath.rs"]
+-pub mod cmath;
+ pub mod env;
+ #[path = "../unsupported/fs.rs"]
+ pub mod fs;
+diff --git a/library/std/src/sys/pal/zkvm/os.rs b/library/std/src/sys/pal/zkvm/os.rs
+index d8739ee3824..759beb2d306 100644
+--- a/library/std/src/sys/pal/zkvm/os.rs
++++ b/library/std/src/sys/pal/zkvm/os.rs
+@@ -5,6 +5,7 @@
+ use crate::io;
+ use crate::marker::PhantomData;
+ use crate::path::{self, PathBuf};
++use crate::sys::os_str;
+ use crate::sys_common::FromInner;
+
+ pub fn errno() -> i32 {
+@@ -111,7 +112,7 @@ pub fn getenv(varname: &OsStr) -> Option<OsString> {
+     // reimplement "os_str" instead of just using the generic unix
+     // "os_str".
+     let u8s: &[u8] = unsafe { crate::slice::from_raw_parts(words.cast() as *const u8, nbytes) };
+-    Some(OsString::from_inner(super::os_str::Buf { inner: u8s.to_vec() }))
++    Some(OsString::from_inner(os_str::Buf { inner: u8s.to_vec() }))
+ }
+
+ pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {