on writer lock. This is first cut at rwlock for rtld. Submitted by: desichen
code until rtld-elf and libkse can cooperate better, those code can be restored. Reviewed by: deischen
path, making them suitable for direct use by the dynamic loader. Register libpthread-specific locking API with rtld on startup. This still has some rough edges with signals which should be addresses later. Approved by: re (scottl)