update PAL and add check-cfg override for target_os

Author: Tropix126

library/std/src/sys/pal/vexos/fs.rs

@@ -340,7 +340,7 @@ impl File {
                 map_fresult(vex_sdk::vexFileSeek(self.fd.0, try_convert_offset(offset)?, SEEK_SET))?
             },
 
-            // vexOS does not allow seeking with negative offsets.
+            // VEXos does not allow seeking with negative offsets.
             // That means we need to calculate the offset from the start for both of these.
             SeekFrom::End(offset) => unsafe {
                 // If our offset is positive, everything is easy
@@ -430,7 +430,7 @@ impl Drop for File {
 pub fn readdir(_p: &Path) -> io::Result<ReadDir> {
     // While there *is* a userspace function for reading file directories,
     // the necessary implementation cannot currently be done cleanly, as
-    // vexOS does not expose directory length to user programs.
+    // VEXos does not expose directory length to user programs.
     //
     // This means that we would need to create a large fixed-length buffer
     // and hope that the folder's contents didn't exceed that buffer's length,
@@ -458,7 +458,7 @@ pub fn remove_dir_all(_path: &Path) -> io::Result<()> {
     unsupported()
 }
 
-pub fn try_exists(path: &Path) -> io::Result<bool> {
+pub fn exists(path: &Path) -> io::Result<bool> {
     let path = CString::new(path.as_os_str().as_encoded_bytes())
         .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "Path contained a null byte"))?;
 

library/std/src/sys/pal/vexos/mod.rs

@@ -16,8 +16,6 @@ pub mod process;
 pub mod stdio;
 #[path = "../unsupported/thread.rs"]
 pub mod thread;
-#[path = "../unsupported/thread_local_key.rs"]
-pub mod thread_local_key;
 pub mod time;
 
 use crate::{arch::asm, ptr::{self, addr_of_mut}};
@@ -37,7 +35,7 @@ pub unsafe extern "C" fn _start() -> ! {
     // Setup the stack
     asm!("ldr sp, =__stack_top", options(nostack));
 
-    // vexOS doesn't explicitly clean out .bss, so as a sanity
+    // VEXos doesn't explicitly clean out .bss, so as a sanity
     // check we'll fill it with zeroes.
     ptr::slice_from_raw_parts_mut(
         addr_of_mut!(__bss_start),