Add support for parallel quantization on Mac

quantization.py

@@ -7,6 +7,7 @@ import bz2
 import torch
 import base64
 import ctypes
+import sys
 from transformers.utils import logging
 
 from typing import List
@@ -142,8 +143,12 @@ class CPUKernel:
                     kernel_file = source_code[:-2] + ".so"
 
                     if compile_parallel_kernel:
-                        compile_command = "gcc -O3 -fPIC -pthread -fopenmp -std=c99 {} -shared -o {}".format(
-                            source_code, kernel_file)
+                        if sys.platform != 'darwin':
+                            compile_command = "gcc -O3 -fPIC -pthread -fopenmp -std=c99 {} -shared -o {}".format(
+                                source_code, kernel_file)
+                        else:
+                            compile_command = "clang -O3 -fPIC -pthread -Xclang -fopenmp -lomp -std=c99 {} -shared -o {}".format(
+                                source_code, kernel_file)
                         print("Compiling", compile_command)
                         exit_state = os.system(compile_command)
                         if not exit_state: