Linking and environment variables for paths

• set PKG_CONFIG_PATH:

  export PKG_CONFIG_PATH=/path/of/first/library/lib/pkgconfig:/path/of/second/library/lib/pkgconfig:$PKG_CONFIG_PATH

• set LD_LIBRARY_PATH:

  export LD_LIBRARY_PATH=/path/of/first/library/lib/:/path/of/second/library/:$LD_LIBRARY_PATH