textutils single threaded performance enhancment

[Padraig Brady]

Hi,

All of textutils are single threaded. However they don't take advantage
of the *_locked() functions, even though 95% of the support config code
is there I think. For e.g. there is ./lib/unlocked-io.h which is indirectly
included by ./src/*.c but there is a #ifdef USE_UNLOCKED_IO around
it. Trying to manually build using this, like:
CPPFLAGS=-DUSE_UNLOCKED_IO ./configure; make
gives compile errors with the wrong number of arguments to being
passed to *_locked(). Also none of ./lib/*.c make any attempt to
#include "unlocked-io.h"

Padraig.