pkg-config命令的用法？

zjracyx

在Gaim-0.74    ./configure时说找不到在/usr/lib/pkconfig下的文件，不知会不会影响编译？
想问一下pkg-config命令的用法，我 想手动添加软件在/usr/lib/pkgconfig下的文件，是否可行？
详情看：

./config.rpath: ./config.rpath: No such file or directory
Package libstartup-notification-1.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libstartup-notification-1.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libstartup-notification-1.0' found
Package mozilla-nss was not found in the pkg-config search path.
Perhaps you should add the directory containing `mozilla-nss.pc'
to the PKG_CONFIG_PATH environment variable
No package 'mozilla-nss' found
Package gtkspell-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gtkspell-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gtkspell-2.0' found