sql.h not found when installing PyODBC on Heroku

I'm trying to install PyODBC on Heroku, but I get fatal error: sql.h: No such file or directory in the logs when pip runs. How do I fix this error?

To follow up on the answer below...

Example for Ubuntu:

sudo apt-get install unixodbc unixodbc-dev

Example for CentOS:

sudo yum install unixODBC-devel

Example for Fedora:

sudo dnf install unixODBC-devel

On Windows:

conn = pyodbc.connect('DRIVER={SQL Server};SERVER=yourserver.yourcompany.com;DATABASE=yourdb;UID=user;PWD=password')

On Linux:

conn = pyodbc.connect('DRIVER={FreeTDS};SERVER=yourserver.yourcompany.com;PORT=1433;DATABASE=yourdb;UID=user;PWD=password;TDS_VERSION=7.2')

You can add Heroku build pack to preinstall required apt packages first

heroku buildpacks:add --index 1 https://github.com/heroku/heroku-buildpack-apt

Add Aptfile in the your directory root and to the repository as well

unixodbc
unixodbc-dev
python-pyodbc
libsqliteodbc

It will install everything you need to work with pyodbc or aioodbc packages from python on Heroku

You need the unixODBC devel package. I don't know what distro you are using but you can google it and build from source.