Item 9: Using pkg-config with Autotools
For many years, developers have struggled with library dependency issues on Unix systems. Many software packages have been inadvertently released without required libraries because Unix systems don't generally require all dependent libraries to be available when linking a library. Additionally, automated build systems have difficulty recognizing and ensuring the existence of secondary library dependencies. Several solutions to this problem have arisen over the years, and the pkg-config project is one of the more successful ones.
pkg-config program looks in well-known and configurable locations in your file system for metadata files describing associated libraries. When you execute
pkg-config with the ...