macos 安装 mysqlclient 时 -lssl gcc

  Running setup.py clean for mysqlclient
Failed to build mysqlclient
Installing collected packages: mysqlclient
  Running setup.py install for mysqlclient ... error
    Complete output from command /Users/machao/Documents/PythonVirtual/py3/bin/python3 -u -c "import setuptools, tokenize;__file__='/private/var/folders/by/c1t20gqd2b3crsh5v7x1gfh80000gn/T/pip-install-unlf6wgo/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 /private/var/folders/by/c1t20gqd2b3crsh5v7x1gfh80000gn/T/pip-record-v50png0t/install-record.txt --single-version-externally-managed --compile --install-headers /Users/machao/Documents/PythonVirtual/py3/bin/../include/site/python3.7/mysqlclient:
    /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'long_description_content_type'
      warnings.warn(msg)
    running install
    running build
    running build_py
    creating build
    creating build/lib.macosx-10.9-x86_64-3.7
    copying _mysql_exceptions.py -> build/lib.macosx-10.9-x86_64-3.7
    creating build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/__init__.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/compat.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/connections.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/converters.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/cursors.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/release.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    copying MySQLdb/times.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb
    creating build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/__init__.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/CLIENT.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/CR.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/ER.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/FLAG.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    copying MySQLdb/constants/REFRESH.py -> build/lib.macosx-10.9-x86_64-3.7/MySQLdb/constants
    running build_ext
    building '_mysql' extension
    creating build/temp.macosx-10.9-x86_64-3.7
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -Dversion_info=(1,3,13,'final',0) -D__version__=1.3.13 -I/usr/local/Cellar/mysql/5.6.27/include/mysql -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -c _mysql.c -o build/temp.macosx-10.9-x86_64-3.7/_mysql.o -g -fno-omit-frame-pointer -fno-strict-aliasing
    _mysql.c:257:6: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                            s = PyUnicode_AsUTF8(item);
                              ^ ~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:287:6: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                            s = PyUnicode_AsUTF8(item);
                              ^ ~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:564:3: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                    _stringsuck(ca, value, ssl);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:553:16: note: expanded from macro '_stringsuck'
            if(t){d=PyUnicode_AsUTF8(t);ssl_keepref[n_ssl_keepref++]=t;}\
                   ^~~~~~~~~~~~~~~~~~~~
    _mysql.c:565:3: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                    _stringsuck(capath, value, ssl);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:553:16: note: expanded from macro '_stringsuck'
            if(t){d=PyUnicode_AsUTF8(t);ssl_keepref[n_ssl_keepref++]=t;}\
                   ^~~~~~~~~~~~~~~~~~~~
    _mysql.c:566:3: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                    _stringsuck(cert, value, ssl);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:553:16: note: expanded from macro '_stringsuck'
            if(t){d=PyUnicode_AsUTF8(t);ssl_keepref[n_ssl_keepref++]=t;}\
                   ^~~~~~~~~~~~~~~~~~~~
    _mysql.c:567:3: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                    _stringsuck(key, value, ssl);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:553:16: note: expanded from macro '_stringsuck'
            if(t){d=PyUnicode_AsUTF8(t);ssl_keepref[n_ssl_keepref++]=t;}\
                   ^~~~~~~~~~~~~~~~~~~~
    _mysql.c:568:3: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
                    _stringsuck(cipher, value, ssl);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    _mysql.c:553:16: note: expanded from macro '_stringsuck'
            if(t){d=PyUnicode_AsUTF8(t);ssl_keepref[n_ssl_keepref++]=t;}\
                   ^~~~~~~~~~~~~~~~~~~~
    _mysql.c:2530:8: warning: assigning to 'char *' from 'const char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
            cname = PyUnicode_AsUTF8(name);
                  ^ ~~~~~~~~~~~~~~~~~~~~~~
    8 warnings generated.
    gcc -bundle -undefined dynamic_lookup -arch x86_64 -g build/temp.macosx-10.9-x86_64-3.7/_mysql.o -L/usr/local/Cellar/mysql/5.6.27/lib -lmysqlclient -lssl -lcrypto -o build/lib.macosx-10.9-x86_64-3.7/_mysql.cpython-37m-darwin.so
    ld: library not found for -lssl
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    error: command 'gcc' failed with exit status 1

    ----------------------------------------
Command "/Users/machao/Documents/PythonVirtual/py3/bin/python3 -u -c "import setuptools, tokenize;__file__='/private/var/folders/by/c1t20gqd2b3crsh5v7x1gfh80000gn/T/pip-install-unlf6wgo/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 /private/var/folders/by/c1t20gqd2b3crsh5v7x1gfh80000gn/T/pip-record-v50png0t/install-record.txt --single-version-externally-managed --compile --install-headers /Users/machao/Documents/PythonVirtual/py3/bin/../include/site/python3.7/mysqlclient" failed with error code 1 in /private/var/folders/by/c1t20gqd2b3crsh5v7x1gfh80000gn/T/pip-install-unlf6wgo/mysqlclient/

根据提示缺少-lssl 貌似是 openssl 的问题

1. 使用 brew install openssl
2. 配置环境变量

    export LDFLAGS="-L/usr/local/opt/openssl/lib"
    export CPPFLAGS="-I/usr/local/opt/openssl/include"

3. pip install mysqlclient 成功