Drop check for sys/bitypes.h

It was obsoleted in 70f3fdf on 2009-02-26.

configure.ac

@@ -194,7 +194,7 @@ AC_HEADER_STDC
 AC_CHECK_HEADERS(fcntl.h unistd.h libc.h sys/dsreq.h sys/select.h \
     sys/time.h sys/shm.h sys/ipc.h sys/signal.h sys/scanio.h os2.h \
     sys/socket.h sys/io.h sys/hw.h sys/types.h linux/ppdev.h \
-    dev/ppbus/ppi.h machine/cpufunc.h sys/bitypes.h sys/sem.h sys/poll.h \
+    dev/ppbus/ppi.h machine/cpufunc.h sys/sem.h sys/poll.h \
     windows.h be/kernel/OS.h limits.h sys/ioctl.h asm/types.h\
     netinet/in.h tiffio.h ifaddrs.h pwd.h getopt.h)
 AC_CHECK_HEADERS([asm/io.h],,,[#include <sys/types.h>])