Update header and lib paths (gh-1)
Update header and lib paths (gh-1)

Update the build script to include the default MacPorts directory in
the header and lib paths

sergeche/libxmljs,CodeFridge/libxmljs_mem,sergeche/libxmljs,rc0x03/libxmljs,isaacs/libxmljs,libxmljs/libxmljs,rc0x03/libxmljs,Konsus/libxml,Visya/libxmljs,polotek/libxmljs,isaacs/libxmljs,improvisio-software/libxmljs,apeace/libxmljs,hildjj/libxmljs,libxmljs/libxmljs,rchipka/libxmljs,gagern/libxmljs,improvisio-software/libxmljs,sergeche/libxmljs,Visya/libxmljs,polotek/libxmljs,isaacs/libxmljs,apeace/libxmljs,rc0x03/libxmljs,Konsus/libxml,CodeFridge/libxmljs_mem,improvisio-software/libxmljs,isaacs/libxmljs,rchipka/libxmljs,hildjj/libxmljs,libxmljs/libxmljs,Konsus/libxml,gagern/libxmljs,Visya/libxmljs,polotek/libxmljs,hildjj/libxmljs,rchipka/libxmljs,gagern/libxmljs,CodeFridge/libxmljs_mem