[tex-live] configure can't handle pathnames with spaces

[Martin Schröder]

Hi,
the pdftex project just got a bug report that our build script can't
handle pathnames with spaces
(http://sarovar.org/tracker/?func=detail&atid=493&aid=856&group_id=106)

Since our build script is just a wrapper around "configure;make", this
most likely applies to texlive also and should better be fixed there.
Also here we can find more shell-foo. :-)

My understanding is that configure crashes because variables like
$ac_config_sub can contain spaces but are not properly quoted when
used.

Best
   Martin