Bug 24993: fix increment

Bug 24993: fix increment

Aparently ((i++)) isn't portable, changed for an admittedly uglier
but functional increment.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Joy Nelson <joy@bywatersolutions.com>
(cherry picked from commit cfd8e38fd8c01d0ab1dfd9e1b828b283b1dac64d)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>