* configure: New file, built by autoconf.
* acconfig.h: New file.
* config.in: New file, built by autoheader.
* Makefile.in: Various changes for new configure script. Also:
(INSTALL): Go up two levels, not one.
(ALLOCA, MALLOC, OPCODES): Remove.
(gencode): Use $(CC_FOR_BUILD).
(case.o): Remove.
(run.o, interp.o): Depend upon config.h.
* interp.c: Include "config.h". Don't include "sysdep.h".
Include <stdlib.h>, <time.h>, and <unistd.h> if they exist.
* run.c: Include "config.h". Don't include "sysdep.h". Include
<stdlib.h> if it exists. Include "getopt.h". Declare printf if
necessary.
