Don't compile in log.cc if we have glog.
Updated.
Check for more libraries and system functions.
More defines to account for those in the source.
Include the core_config.h file to pick up build time definitions.
Also check the mach/mach_time.h header file.
Don't pick up stat64 on MacOS as it's been deprecated. Define instead _DARWIN_USE_64_BIT_INODE before including the relevant header files.
Move the sys/uio.h include to pick up additional definitions needed.
Prefer F_FULLFSYNC on MacOS X.