Cygwin init:

- in a cygwin terminal window:
  * run shell/bin/init-cygwin.sh:
    + it creates windows env variables VM_HOMES en MY_HOME
    + these variables are also exported to the shell env.
  * run cygwin-monts.sh:
    + this will mount:
       . /cygdrive/c on /c
       . $VM_HOMES/cyghome on /home , the directory is created if it not already exists
  * stop the shell, now it's possible to run an XWindow env
- in a shell from the cyg terminal or an XWindows env: