DESCRIPTION
===========
Performing a pattern match of a Regex resulting into a very
large string, leads to crash due to failed realloc().

ANALYSIS
========
dupl() calls enlarge(). It in turn calls realloc() for
pointer p->strip. This eventually fails due to OOM.
However we are still using the same pointer in memcpy()
causing a SEGFAULT!

FIX
===
1) In dupl(), checking for error code (which would be set
if realloc fails) immediately after call to enlarge().
Returning now with this error code.

2) Handling the same in the caller functions.