pkg-config retrieves information about
packages from special metadata files.
These files are named after the
package, with the extension .pc. By
default, pkg-config looks in the
directory prefix/lib/pkgconfig for
these files; it will also look in the
colon-separated (on Windows,
semicolon-separated) list of
directories specified by the
PKG_CONFIG_PATH environment variable.
Best Answer
http://linux.die.net/man/1/pkg-config