cannot find libnautilus-extension in the repo just libnautilus and dbg 
which I take as for debugging. and I am not knowing what I'll be lacking 
with Dropbox if I figure out how to modify that PKG_CONFIG_PATH and CFLAGS 
and get it to install as I'd like to have the complete package installed 

checking for NAUTILUS... configure: error: Package requirements 
(libnautilus-extension >= 2.16.0) were not met:

No package 'libnautilus-extension' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables NAUTILUS_CFLAGS
and NAUTILUS_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.