On my Mac under OSX 10.8, I tried to set this to `'glibtoolize'`, but it can’t find it in the PATH.
```
==> sh autogen.sh
glibtoolize failed:
autogen.sh: line 13: glibtoolize: command not found
```

Same thing with `aclocal`, `autom4te`, `automake`, `autoheader` and `autoconf`.