idl2wrs: some code cleanups.

idl2wrs: some code cleanups.

Code cleanups include:
- sanity checks for malloc()
- change forbidden APIs into g_* versions
- minor indentation fixes
- add modeline
- add compilation for cmake and autotools

Bug: 11052
Change-Id: I825f04d9703448f9165d188be2bdd185fce5ff5d
Reviewed-on: https://code.wireshark.org/review/10030
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>