I am on an up-to-date Ubuntu 12.04 system. I have unixodbc (v2.2.14 from ubuntu repos), MySQL and its relevant drivers installed. Also connected to a valid DSN. Verified by issuing
isql DBName UName passwd
find / -iname sql.h -print
You need to install the
unixodbc-dev package to get the development header files.
sudo apt-get install unixodbc-dev
-dev packages contain the require header files required to compile and build programs using these headers to make calls to the library. The library files themselves would be part of the regular package i.e.
unixodbc in your case.
If you want to know which package provides a certain file, you could use
sudo apt-file update sudo apt-file find sql.h