Leave more space for extensions in pthread_rwlockattr_t

Change pthread_rwlockattr_t from int to long. On LP64 this gives us more
room for extensibility since longs are 8 bytes. glibc also reserves 8
bytes for this.

Bug: 14582681
Bug: 12875898
Change-Id: I55d599be0fdbbf0cb55957ec0ea62ab042bdee94
1 file changed