These are m4 macros used by autoconf. Many come from:
http://www.gnu.org/software/ac-archive/htmldoc/index.html

gsl.m4, which did exist in version of atlc up to 4.4.5
has been removed, as the gsl library is no logner needed
as the functionality has been included in the atlc
source. 

Re: atlc-4.5.0 10th October 2003