问题1：下载源码解压后使用python setup.py install返回错误：
python setup.py install
running install
running bdist_egg
running egg_info
writing psycopg2.egg-info/PKG-INFO
writing dependency_links to psycopg2.egg-info/dependency_links.txt
writing top-level names to psycopg2.egg-info/top_level.txt
Error: pg_config executable not found.
pg_config is required to build psycopg2 from source. Please add the directory
containing pg_config to the $PATH or specify the full executable path with the
option:
python setup.py build_ext --pg-config /path/to/pg_config build ...
or with the pg_config option in 'setup.cfg'.
If you prefer to avoid building psycopg2 from source, please install the PyPI
'psycopg2-binary' package instead.
For further information please check the 'doc/src/install.rst' file (also at
<http://initd.org/psycopg/docs/install.html>).
按网上解决方案首先需要先安装postgresql，运行命令：
brew install postgresql安装完成后再次执行命令，则报错：
python setup.py install
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