在使用pip install pillow命令时，安装出错，提示如下：
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -DTHREAD_STACK_SIZE=0x100000 -fPIC -Isrc/Tk -I/tmp/pip-install-xr8nqb_8/pillow/src/libImaging -I/tmp/pip-install-xr8nqb_8/pillow -I/usr/include -I/usr/include/python3.6m -c src/_imagingtk.c -o build/temp.linux-x86_64-3.6/src/_imagingtk.o
src/_imagingtk.c:16:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
src/_imaging.c:74:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
building 'PIL._imagingmath' extension
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -DTHREAD_STACK_SIZE=0x100000 -fPIC -I/tmp/pip-install-xr8nqb_8/pillow/src/libImaging -I/tmp/pip-install-xr8nqb_8/pillow -I/usr/include -I/usr/include/python3.6m -c src/_imagingmath.c -o build/temp.linux-x86_64-3.6/src/_imagingmath.o
building 'PIL._imagingmorph' extension
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -DTHREAD_STACK_SIZE=0x100000 -fPIC -I/tmp/pip-install-xr8nqb_8/pillow/src/libImaging -I/tmp/pip-install-xr8nqb_8/pillow -I/usr/include -I/usr/include/python3.6m -c src/_imagingmorph.c -o build/temp.linux-x86_64-3.6/src/_imagingmorph.o
src/_imagingmath.c:16:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
src/_imagingmorph.c:14:20: fatal error: Python.h: No such file or directory
#include "Python.h"
^
compilation terminated.
compilation terminated.
error: command 'gcc' failed with exit status 1
----------------------------------------
Command "/usr/bin/python3.6 -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-xr8nqb_8/pillow/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-record-0wrtmkzl/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-install-xr8nqb_8/pillow/
FATAL: Failed installing package pillow找不到Python.h头文件，没有gcc之类的问题其实都是因为从Pillow 3.0.0.开始需要libjpeg?和?zlib两个包才能编译，现在下载的Pillow里没有这两个包，所以下载失败
换个指令下载就行：
pip install --upgrade pillow
