added a small test prg for serial in

serial/t.c

@@ -0,0 +1,21 @@
+
+
+#include  <stdio.h>
+
+#include  "serial.h"
+
+int main (int argc, char *argv[])
+{
+int	serial_in;
+int	byte, foo;
+
+serial_in = prepare_UART("/dev/ttyS0", 9600);
+fprintf(stderr, "prepare uart -> %d\n", serial_in);
+
+for (foo=0; foo<20; foo++) {
+	byte = getbyte(serial_in);
+	printf("%6d    %02x\n", foo, byte);
+	}
+
+return 0;
+}