Add check bison version in configure.ac file.
To build correctly matiec we need bison greater or equals than 2.4 version.
Now the "configure" script is able to check if system has correctly requirements.
FUNCTION_BLOCK DELAY (* N-sample delay *)
VAR_INPUT
RUN : BOOL ; (* 1 = run, 0 = reset *)
XIN : REAL ;
N : INT (* 0 <= N < 128 or manufacturer- *)
END_VAR (* specified maximum value *)
VAR_OUTPUT XOUT : REAL; END_VAR (* Delayed output *)
VAR X : ARRAY [0..127] (* N-Element queue *)
OF REAL; (* with FIFO discipline *)
I, IXIN, IXOUT : INT := 0;
END_VAR
IF RUN THEN IXIN := MOD(IXIN + 1, 128) ; X[IXIN] := XIN ;
IXOUT := MOD(IXOUT + 1, 128) ; XOUT := X[IXOUT];
ELSE XOUT := XIN ; IXIN := N ; IXOUT := 0;
FOR I := 0 TO N DO X[I] := XIN; END_FOR;
END_IF ;
END_FUNCTION_BLOCK