MacOSX

1. Made binary cmigemo work on Mac OSX other than directory where cmigemo was compiled.
2. Fixed 'clean'.  Made dict/utf-8.d/ is cleaned.

Tested with 
$ cd MIGEMO-COMPILE-DIR
$ make osx-clean
$ make osx-distclean
./configure --prefix=$HOME/local
$ make osx-all
$ make osx-intall

$ dyldinfo -dylibs build/cmigemo 
attributes     dependent dylibs
                /Users/MYNAME/local/lib/libmigemo.1.dylib
                /usr/lib/libSystem.B.dylib