added functions sanei_thread_sendsig() and sanei_thread_get_status()
changed behaviour of sanei_thread_waitpid(), changed parameters
of sanei_thread_begin()
pthread support, added switch --enable-fork-process which toggles
between the usage of fork and pthread, set the default behaviour to
pthread usage on Darwin
* include/sane/config.h: added the HAVE_LIBPTHRAD stuff
* sanei/sanei_thread.c include/sane/sanei_thread.h: fixed compilation issue
on OS/2, added support for fork too, so that we can use sanei_thread
functions in any case.
* backend/plustek.[ch]: changes due to the sanei_thread-lib work
added linker option -lpthread if pthread.h is found
* include/sane/config.in.h: added HAVE_PTHREAD_H
* sanei/sanei_thread.c include/sane/sanei_thread.h: added pthread_
functions to library, so every backend is able to use either fork or
pthread for its reader-process - see plustek backend for example
* backend/plustek.h backend/plustek.c: added sanei_thread stuff to support
threading on MacOS X
* backend/plustek_pp*: some cleanup
Gerhard Jaeger