Compare new aclocal.m4 to old one, and preserve timestamp if not updated, to make boostrapping *blindingly* fast with Autoconf 2.52b.
Compare new aclocal.m4 to old one, and preserve timestamp if not
updated, to make boostrapping *blindingly* fast with Autoconf 2.52b.

Alexpux/Coin3D,Alexpux/Coin3D,Alexpux/Coin3D,Alexpux/Coin3D