The Solaris version of os::naked_sleep calls usleep, while all other POSIX ports call nanosleep. The reason for the Solaris difference is that use of nanonsleep requires -lrt. But it appears that on Solaris we are linking with -lrt. (See flags.m4 "Set $2JVM_LIBS (per os)".)

This suggests we could merge all the POSIX versions. (Windows of course remains different.)