The type WT_SPINLOCK can be configured at build time to be one of 4 variations:

1. Custom spinlock implementation (NOT pthread_spin_lock).
2. Windows critical section with spinlock count : effectively mixed semantics.
3. POSIX thread mutex
4. POSIX thread adaptive mutex

By default on systems that support posix mutexes we default to using a plain posix mutex, this includes when built as part of mongodb.

As spinlock identifies a specific type of lock behavior, this name is misleading in the general case.

First step:

Identify if we can (no name collision) and want to use an abstract name such as WT_LOCK, or if we think the lock types should reflect their implementation.