[GRASS-dev] fix for bug in i.atcorr in grass-svn

[Yann]

In grass-svn:

6s.cpp does not compile because it does not find def for memcpy() and memset()

similarly:
AerosolModel.cpp:861: error: ‘exit’ was not declared in this scope

Adding this to common.h fixes the errors:
#include "stdio.h"
#include "stdlib.h"
#include "string.h"

yann