在虚拟环境下pip install mysqlclient报错，在源环境下pip install myclient没问题，pip3 install也同样报错，虚拟环境下的是python3版本。
报错如下

Building wheels for collected packages: mysqlclient
  Building wheel for mysqlclient (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: /www/weixin_app/weixin_flask/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/setup.py'"'"'; __file__='"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-7xut5l8i --python-tag cp36
       cwd: /tmp/pip-install-1cbtwqm6/mysqlclient/
  Complete output (31 lines):
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-3.6
  copying _mysql_exceptions.py -> build/lib.linux-x86_64-3.6
  creating build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/__init__.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/compat.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/converters.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/connections.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/cursors.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/release.py -> build/lib.linux-x86_64-3.6/MySQLdb
  copying MySQLdb/times.py -> build/lib.linux-x86_64-3.6/MySQLdb
  creating build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/__init__.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/CR.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/ER.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/FLAG.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/REFRESH.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  copying MySQLdb/constants/CLIENT.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
  running build_ext
  building '_mysql' extension
  creating build/temp.linux-x86_64-3.6
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -Dversion_info=(1,3,1,'final',1) -D__version__=1.3.1 -I/www/server/mysql/include -I/usr/include/python3.6m -c _mysql.c -o build/temp.linux-x86_64-3.6/_mysql.o -g -fabi-version=2 -fno-omit-frame-pointer -fno-strict-aliasing
  _mysql.c:29:20: fatal error: Python.h: No such file or directory
   #include "Python.h"
                      ^
  compilation terminated.
  error: command 'gcc' failed with exit status 1
  ----------------------------------------
  ERROR: Failed building wheel for mysqlclient
  Running setup.py clean for mysqlclient
Failed to build mysqlclient
Installing collected packages: mysqlclient
    Running setup.py install for mysqlclient ... error
    ERROR: Command errored out with exit status 1:
     command: /www/weixin_app/weixin_flask/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/setup.py'"'"'; __file__='"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/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-lbbrwnn1/install-record.txt --single-version-externally-managed --compile --install-headers /www/weixin_app/weixin_flask/include/site/python3.6/mysqlclient
         cwd: /tmp/pip-install-1cbtwqm6/mysqlclient/
    Complete output (31 lines):
    running install
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.6
    copying _mysql_exceptions.py -> build/lib.linux-x86_64-3.6
    creating build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/__init__.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/compat.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/converters.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/connections.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/cursors.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/release.py -> build/lib.linux-x86_64-3.6/MySQLdb
    copying MySQLdb/times.py -> build/lib.linux-x86_64-3.6/MySQLdb
    creating build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/__init__.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/CR.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/ER.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/FLAG.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/REFRESH.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    copying MySQLdb/constants/CLIENT.py -> build/lib.linux-x86_64-3.6/MySQLdb/constants
    running build_ext
    building '_mysql' extension
    creating build/temp.linux-x86_64-3.6
    gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -Dversion_info=(1,3,1,'final',1) -D__version__=1.3.1 -I/www/server/mysql/include -I/usr/include/python3.6m -c _mysql.c -o build/temp.linux-x86_64-3.6/_mysql.o -g -fabi-version=2 -fno-omit-frame-pointer -fno-strict-aliasing
    _mysql.c:29:20: fatal error: Python.h: No such file or directory
     #include "Python.h"
                        ^
    compilation terminated.
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /www/weixin_app/weixin_flask/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/setup.py'"'"'; __file__='"'"'/tmp/pip-install-1cbtwqm6/mysqlclient/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-lbbrwnn1/install-record.txt --single-version-externally-managed --compile --install-headers /www/weixin_app/weixin_flask/include/site/python3.6/mysqlclient Check the logs for full command output.