[crac] RFR: macOS build fixes

[Roman Marchenko]

This changeset fixes build warnings and errors occured on macOS.

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Commit messages:
 - Fixing macOS build

Changes: https://git.openjdk.org/crac/pull/92/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=92&range=00
  Stats: 8 lines in 2 files changed: 4 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/crac/pull/92.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/92/head:pull/92

PR: https://git.openjdk.org/crac/pull/92