Arch Linux

Description:
Upon trying to compile ettercap by running
$ makepkg -s
on the official PKGBUILD, configure fails printing the following:
----------
checking for correct ltmain.sh version... grep: character class syntax is [[:space:]], not [:space:]
no

*** Gentoo sanity check failed! ***
*** libtool.m4 and ltmain.sh have a version mismatch! ***
*** (libtool.m4 = 1.5.18, ltmain.sh = ) ***

Please run:

libtoolize --copy --force

if appropriate, please contact the maintainer of this
package (or your distribution) for help.
----------
I don't know if this happens in i686 systems (tough it probably does).

Additional info:
Version is NG_0.7.3-15


Steps to reproduce:
cd to the directory with the ettercap PKGBUILD and run makepkg -s as a normal user.


The problem is that configure runs this:
gentoo_ltmain_version=`grep '^[:space:]*VERSION=' $ltmain | sed -e 's|^[:space:]*VERSION=||'`
to determine the version of the ltmain.sh file. But as it seems, [:space:] doesn't work with grep (anymore?):
$ grep '[:space:]' ltmain.sh
grep: character class syntax is [[:space:]], not [:space:]
As the error suggests, replacing [:space:] with [[:space:]] solves the problem.
I've uploaded two files: a patch to be applied to the PKGBUILD, and a file to be included along with the PKGBUILD. (The second file patches the configure script. I used the 01_pointers_and_ints_dont_mix.diff patch that is already included as a reference to make it, as I'm not familiar with the conventions used in these cases. Feel free to modify anything that may be wrong.)