libpcre for debian
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I wrote my own makefile for this (actually, it is based on the one that I
used with pcre 2.x, where I had to write my own in order to get shared
libraries). The upstream makefile doesn't build shared libraries properly,
and I don't know enough about libtool to work out why not.

The other change I made is to prefix the names of the functions in libpcreposix
with "pcreposix_". This is required so they don't clash with the ones in
libc. Suitable #defines have been added to pcreposix.h so that the
unprefixed names can be used.