使用virtualenv安装了tensorflow，但运行的时候发现CPU可以支持AVX2和FMV，但需要从源码重新构建。好吧，那就开始吧～
参考：
1. 环境
系统：macOS High Sierra 10.13.4
python：2.7.15（系统自带）
2. 准备
2.1 避免冲突
我在前面已经用virtualenv创建了tensorflow的环境，此前创建的目录名称“tensorflow”，怕产生冲突，将虚拟环境的目录名称修改为“vir-tensorflow”
2.2 克隆代码库
打开终端，输入以下命令：
$ git clone https://github.com/tensorflow/tensorflow
此时，会在用户目录下创建一个“tensorflow”的目录（幸亏刚刚该虚拟环境目录的命名了～～）
下载的时间比较长，请耐心等待～～快受不了公司的网速了！！！！！
2.3 针对macOS准备环境
2.3.1 安装bazel
使用brew安装：
brew install bazel #安装
bazel version #查看是否安装成功
brew upgrade bazel #升级版本
2.3.2 安装python依赖项
必须安装软件包：
six
numpy：数值处理
wheel：管理wheel格式的python压缩包
使用pip来安装：
$ sudo pip install six numpy wheel
当前版本：
six——1.11.0，numpy——1.14.3，wheel——0.31.0
2.4 安装配置
2.4.1 软件包配置
克隆源码库到本地后，在根目录中包含有一个名为“configure”的bash脚本。必须先运行该脚本，然后才能创建pip软件包并安装TensorFlow。
$ cd /xxxx/tensorflow
$ ./configure
进入tensorflow源码树的根目录，执行configure的bash脚本。
此时configure脚本会向您提出若干问题。我选择默认值，针对本机CPU类型优化所生成的代码，但是这样构建出来的TensorFlow是无法在其他类型的CPU上运行的。
以下是我运行configure脚本时的问题选择：
Extracting Bazel installation...
You have bazel 0.13.0-homebrew installed.
Please specify the location of python. [Default is /usr/local/opt/python@2/bin/python2.7]: /usr/bin/python2.7
Found possible Python library paths:
/Library/Python/2.7/site-packages
Please input the desired Python library path to use. Default is [/Library/Python/2.7/site-packages]
/Library/Python/2.7/site-packages
Do you wish to build TensorFlow with Google Cloud Platform support? [Y/n]: N
No Google Cloud Platform support will be enabled for TensorFlow.
Do you wish to build TensorFlow with Hadoop File System support? [Y/n]: N
No Hadoop File System support will be enabled for TensorFlow.
Do you wish to build TensorFlow with Amazon S3 File System support? [Y/n]: N
No Amazon S3 File System support will be enabled for TensorFlow.
Do you wish to build TensorFlow with Apache Kafka Platform support? [Y/n]: N
No Apache Kafka Platform support will be enabled for TensorFlow.
Do you wish to build TensorFlow with XLA JIT support? [y/N]: N
No XLA JIT support will be enabled for TensorFlow.
Do you wish to build TensorFlow with GDR support? [y/N]: N
No GDR support will be enabled for TensorFlow.
Do you wish to build TensorFlow with VERBS support? [y/N]: N
No VERBS support will be enabled for TensorFlow.
Do you wish to build TensorFlow with OpenCL SYCL support? [y/N]: N
No OpenCL SYCL support will be enabled for TensorFlow.
Do you wish to build TensorFlow with CUDA support? [y/N]: N
No CUDA support will be enabled for TensorFlow.
Do you wish to download a fresh release of clang? (Experimental) [y/N]: N
Clang will not be downloaded.
Do you wish to build TensorFlow with MPI support? [y/N]: N
No MPI support will be enabled for TensorFlow.
Please specify optimization flags to use during compilation when bazel option "--config=opt" is specified [Default is -march=native]: -march=native
Would you like to interactively configure ./WORKSPACE for Android builds? [y/N]: N
Not configuring the WORKSPACE for Android builds.
Preconfigured Bazel build configs. You can use any of the below by adding "--config=<>" to your build command. See tools/bazel.rc for more details.
--config=mkl # Build with MKL support.
--config=monolithic # Config for mostly static monolithic build.
Configuration finished
2.4.2 软件包构建
配置后，进行构建：
$ bazel build --config=opt //tensorflow/tools/pip_package:build_pip_package
报错了！！！！！
Starting local Bazel server and connecting to it...
................
WARNING: /private/var/tmp/_bazel_yujianwen/7cea4d7c61741771d65fc25d431ce59d/external/protobuf_archive/WORKSPACE:1: Workspace name in /private/var/tmp/_bazel_yujianwen/7cea4d7c61741771d65fc25d431ce59d/external/protobuf_archive/WORKSPACE (@com_google_protobuf) does not match the name given in the repository's definition (@protobuf_archive); this will cause a build error in future versions
ERROR: /private/var/tmp/_bazel_yujianwen/7cea4d7c61741771d65fc25d431ce59d/external/local_config_cc/BUILD:50:5: in apple_cc_toolchain rule @local_config_cc//:cc-compiler-armeabi-v7a: Xcode version must be specified to use an Apple CROSSTOOL. If your Xcode version has changed recently, try: "bazel clean --expunge" to re-run Xcode configuration
ERROR: While resolving toolchains for target //tensorflow/tools/pip_package:simple_console: Analysis of target '@local_config_cc//:cc-compiler-armeabi-v7a' failed; build aborted
ERROR: Analysis of target '//tensorflow/tools/pip_package:build_pip_package' failed; build aborted: Analysis of target '@local_config_cc//:cc-compiler-armeabi-v7a' failed; build aborted
INFO: Elapsed time: 17.909s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (64 packages loaded)
currently loading: tensorflow/python ... (3 packages)
Error: Xcode version must be specified to use an Apple CROSSTOOL
处理：
应该是Xcode使用版本与系统版本不一致，需要修改Xcode版本
本机Xocde版本：9.3.1
$ sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
$ bazel clean --expunge
执行以上指令后，重新构建，没有Error，可以往下执行~~~
过了一个中午，还是构建过程还是出现error，一共20个。停止了～～～
