This directory contains the pkg-config module files of the dependencies of the project, by platform and "build type" (i.e. using either system libraries or embedded libraries).

During a build, pkg-config will search for a module file in these directories, in this order:

1. <platform>/embedded/<module_name> (unless USE_SYSTEM_LIBS is passed to the rake build command)
2. <platform>/system/<module_name>
3. default pkg-config paths of the environment

The "embedded/" module files define the flags to compile and link against the libraries provided in the datadog-agent package.

The "system/" files should only be present for dependencies that don't provide pkg-config files for the platform. They define the flags to compile and link against the libraries provided by the system.

cgo uses pkg-config to determine which compiler and linker flags to use when the following directive is present in the go source file:

// #cgo pkg-config <module_name>

(see https://golang.org/cmd/cgo/ for more details on cgo usage)