error when make parameter_server in MacOS 10.10.4

error msg:
In file included from src/util/file.cc:1:
In file included from ./src/util/file.h:8:
In file included from ./src/util/common.h:42:
./src/util/resource_usage.h:35:17: error: use of undeclared identifier 'CLOCK_MONOTONIC_RAW'
clock_gettime(CLOCK_MONOTONIC_RAW, &tv);

gcc version:
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin14.4.0
Thread model: posix