Building from source without homebrew or any other package manager.
Download the latest version of the [https://pkg-config.freedesktop.org/releases/?C=M;O=A](pkg-config source).
LDFLAGS="-framework CoreFoundation -framework Carbon" ./configure --with-internal-glib
make
sudo make install
OSX & iOS uses a mechanism for managing development resources such as a libraries called Frameworks. These are generally frameworks in the Software Engineering sense however might also just be libraries. The flag informs the tool chain to build against these libraries.
See Apple's documentation about it for more details.