Define HAVE_CLOCKGETTIME on Linux for pip install

setup.py

@@ -20,16 +20,17 @@ def compile_test(header, library):
 FILES = glob.glob('util/*.cc') + glob.glob('lm/*.cc') + glob.glob('util/double-conversion/*.cc') + glob.glob('python/*.cc')
 FILES = [fn for fn in FILES if not (fn.endswith('main.cc') or fn.endswith('test.cc'))]
 
+#We don't need -std=c++11 but python seems to be compiled with it now.  https://github.com/kpu/kenlm/issues/86
+ARGS = ['-O3', '-DNDEBUG', '-DKENLM_MAX_ORDER='+max_order, '-std=c++11']
+
 if platform.system() == 'Linux':
     LIBS = ['stdc++', 'rt']
+    ARGS.append('-DHAVE_CLOCKGETTIME')
 elif platform.system() == 'Darwin':
     LIBS = ['c++']
 else:
     LIBS = []
 
-#We don't need -std=c++11 but python seems to be compiled with it now.  https://github.com/kpu/kenlm/issues/86
-ARGS = ['-O3', '-DNDEBUG', '-DKENLM_MAX_ORDER='+max_order, '-std=c++11']
-
 #Attempted fix to https://github.com/kpu/kenlm/issues/186 and https://github.com/kpu/kenlm/issues/197
 if platform.system() == 'Darwin':
     ARGS += ["-stdlib=libc++", "-mmacosx-version-min=10.7"]