Add Condvar to mc-sgx-sync crate

[nick-mobilecoin]

Add condvar.rs implementation which more or less copies from
rust source at
606c3907

[nick-mobilecoin]

Current dependencies on/for this PR:

• main
  • PR Update CI for SGX SDK action update #14
    • PR Move panic to panic/abort #13
      • PR Add untrusted side of stderr from enclave #15
        • PR Add mc-sgx-io #22
          • PR Add mc-sgx-panic-log #24
            • PR Add mc-sgx-panic crate for common panic handling #30
              • PR Add panicking::panic_count to mc-sgx-panic #31
                • PR Update CODEOWNERS file #32
                  • PR Add panicking::panicking() function #33
                  • PR Add public function thread::panicking() #34
                  • PR Add mc-sgx-sync crate #35
                  • PR Add poison.rs to mc-sgx-sync crate #36
                  • PR Add sys module to mc-sgx-sync #39
                  • PR Add mutex.rs to mc-sgx-sync crate #40
                  • PR Use a static buffer for panic messages #41
                  • PR Add mc-sgx-sync::sys::locks::Condvar #42
                  • PR Add Condvar to mc-sgx-sync crate #43 👈
                  • PR Add mc-sgx-sync::sys::locks::RwLock #44
                  • PR Add RwLock to mc-sgx-sync #45
                  • PR Add example usage for mc-sgx-sync and std::sync #46
                  • PR Merge panic-abort and panic-log crates into mc-sgx-panic #48
                  • PR Prevent recursive panics from happening #50
                  • PR Remove unneeded traits on sys types #51
        • PR Rename mc-sgx-io to mc-sgx-io-untrusted #21

This comment was auto-generated by Graphite.

[codecov-commenter]

Codecov Report

Merging #43 (f9042d6) into nick/sys-condvar (c9f2e88) will not change coverage.
The diff coverage is n/a.

@@                Coverage Diff                @@
##           nick/sys-condvar      #43   +/-   ##
=================================================
  Coverage             92.85%   92.85%           
=================================================
  Files                     8        8           
  Lines                   322      322           
=================================================
  Hits                    299      299           
  Misses                   23       23           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[NotGyro]

Looks good to me!

[nick-mobilecoin]

⏳ This pull request is set to merge as part of a Graphite merge job
Stack job ID: uCoNH97G95Be2subCEb9.
See details on graphite.dev

[nick-mobilecoin]

@samdealy requesting re-review since I had to restack this