set 'default-zpublisher-encoding utf-8' otherwise we can have exception in Localizer with non iso-8859-15 characters. set other encoding variables as well.

Install is updatable, so it is safe to call it this way.

set GLIB_CFLAGS and GLIB_LIBS variables so that the initial compilation without having pkg-config works.

This reverts commit 168ca54c.

md5sum change was missing.

From changelog:

Make buildout.rmtree working with symlink as a path argument.
  https://bugs.launchpad.net/zc.buildout/+bug/144228

; is dangerous character, so just use newlines to separate commands.

It will make tracking bug easier. Also explain reason of debug info.

Sometimes .git disappears, and bt5 and product/ERP5/bootstrap changes
permission. Thanks to listing directory contents it will allow to know if
state of directory is correct before git pull.

; are used in order to allow to progress in case of issue, as ls shall not
generate part installation error.