Some useful pkg-config tricks

[Jef Driesen]

Hi,

I've noticed people are having trouble with pkg-config not finding 
libraries (e.g. libdivecomputer) installed to non-standard locations, or 
when cross-compiling. I'm not sure if you are aware of this, but 
pkg-config supports environment variables to influence its search path:

http://linux.die.net/man/1/pkg-config

PKG_CONFIG_PATH

Use this variable to specify additional directories to add to the 
default search path. This is very convenient if you have installed 
libraries to a non-default location. For example if you have installed 
libdivecomputer to $HOME/local, you can do:

export PKG_CONFIG_PATH=$HOME/local/lib/pkgconfig

and then pkg-config will find libdivecomputer there.

PKG_CONFIG_LIBDIR

Use this variable to replace the default pkg-config search directory. 
This is useful when cross-compiling. Normally the pkg-config of the host 
system will search packages for the host system, and that's not what you 
want. With PKG_CONFIG_LIBDIR, you can override the default directory and 
force pkg-config to search in a different directory. For example if you 
use mingw as a cross-compiler and install the windows packages to 
$HOME/windows, you can do:

export PKG_CONFIG_LIBDIR=$HOME/windows/lib/pkgconfig

and then pkg-config will only search there.

Jef