Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. What does this mean ?
PKG_CONFIG_PATH is a environment variable which holds the path of pkg-config script.
To find the path use the command
and your results will be something like this
To check the PKG_CONFIG_PATH value use the command
To set the PKG_CONFIG_PATH value use
It means you're trying to build something from source, and it can't find all of the dependencies it needs. The