[libc][POSIX][pthreads] implement pthread_condattr_t functions (#88987)

Implement:
- pthread_condattr_destroy
- pthread_condattr_getclock
- pthread_condattr_getpshared
- pthread_condattr_init
- pthread_condattr_setclock
- pthread_condattr_setpshared

Fixes: #88581
diff --git a/libc/src/pthread/pthread_condattr_getclock.cpp b/libc/src/pthread/pthread_condattr_getclock.cpp
new file mode 100644
index 0000000..a3a3963
--- /dev/null
+++ b/libc/src/pthread/pthread_condattr_getclock.cpp
@@ -0,0 +1,25 @@
+//===-- Implementation of the pthread_condattr_getclock -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_condattr_getclock.h"
+
+#include "src/__support/common.h"
+
+#include <pthread.h>   // pthread_condattr_t
+#include <sys/types.h> // clockid_t
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, pthread_condattr_getclock,
+                   (const pthread_condattr_t *__restrict attr,
+                    clockid_t *__restrict clock_id)) {
+  *clock_id = attr->clock;
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE