Installing MySQL-python causes command 'clang' failed with exit status 1 on Mac OS 10.13.15

I just resolved this exact issue when running Ansible's mysql_user module. The answer here helped tip me off to a solution. I also needed MySQL-python from pip, which also broke in this process, so I've added the extra steps.

Steps to resolve:

1. brew unlink mysql # only if installed, causes the next step to fail
2. brew install mysql-connector-c
3. locate mysql_config file with which (mysql_config)

4. edit the mysql_config file, under # Create options change this:

   libs="$libs -l "

   to this:

   libs="$libs -lmysqlclient -lssl -lcrypto"

   if using vim, :wq! to save the read-only file

5. Now the install should run successfully

   pip install mysqlclient

6. Adding this separately, as it's similar but not directly related to the initial question

   pip install MySQL-python

7. Fix mysql brew formula, if it was unlinked in the first step.

   brew unlink mysql-connector-c

   brew link mysql

I fixed it by passing the OpenSSL path:

env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install mysqlclient

You can see the full article of the solution done by MrWeeble

I solved this issue by setting xcode-select to use non-XCode command line tools, as shown in the below answer. I had a related clang error which led me to this answer.

sudo xcode-select --switch /Library/Developer/CommandLineTools

https://stackoverflow.com/a/30902106/11614142