Problem Solved!!! Finally, I was able to solved this mysterious problem. I spent long time tracing through the output from running 'configure'. It paid off when I took notice of a line (repeated 3 times): "warning : you need bison if you need to parse text". So now I know, bison wasn't installed on my mandrake OS. Well, I guess, from this experience, never ASSUME ur system to have all the neccessary stuff pre-installed!!! I think, one gd point for the PHP developer/packager is that, their configure script can stop the process if any compulsory stuff is missing from a system instead of continuing with just a little insignificant warning sign among lines & lines of text output on the screen!!!!
