Without telling us (a) where and how you installed xeresc or (b) where Eclipse is installed, it's a little hard to give accurate directions for solving.
However - put simply, the compiler doesn't know where to find the files.
I recently used Code::Blocks on my Desktop machine to try a project I'd been working on with my laptop. When I did this, much to my horror - gdiplus.h wasn't found. Nor for that matter was glext.h and a few others.
Now, in the #includes section of my code these files were included like so:
#include <gdiplus.h>
#include <GL/gdiplus.h>
Since I have Code::Blocks installed in C:\Program Files(x86)\CodeBlocks, the compiler - MingGW resides in C:\Program Files (x86)\CodeBlocks\MinGW
This meant that I had to:
(a) copy gdiplus.h to C:\Program Files (x86)\CodeBlocks\MinGW\include\gdiplus.h
(b) copy glext.h to C:\Program Files (x86)\CodeBlocks\MinGW\include\GL\glext.h