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.

Remove remaining signed/unsigned comparison error messages when compiling.

Remove warning about comparisons between int and unsigned int.

Support for data types of STEP.T and STEP.X in SFCs

Remove dead code.

Change code formatting (alignment)

Aloow use of SFC STEPs as variables.

Check lvalues in expressions passed to Function/FB IN parameters.

Fix comment (bug found by Manuele).

Remove warning about redefining "__STDC_LIMIT_MACROS" (bug found by Manuele).

Constant folding for IL.

update comments.

fix bug: remove REAL from candidate datatypes when real constant has overflowed.

signed integer limits do not affect ANY_INT constant values.

comment out un-used code.

cleaning up code. Changing HUGE_VAL to INFINITY.

Cleaning up the code.

Clean up the code a little.

Fixing includes to define INTxx_MAX etc...

Add remove_from_candidate_datatype_list method using constant_folding results.

fix typo.

fix parsing of non base 10 constant values.

determine const value of hex, octal and bin literals correctly.

fix array bounds check.

Fix stupid typos (in calculating array dimension)!

Add file missing from previous commit.

Add ERROR_MSG macro && move extract_XXX() functions to constant_folding.cc

Add independent extract_integer() function (preparing to remove extract_XXX() from absyntax_utils.cc)

Clean up code (remove parsing of integers in stage 4).

Fix literal MACRO gcc compliant.

Add 'dimension' parameter to subrange_c, fill it correctly, and use it.

extract_int64() must not handle negation operation (was doing it incorrectly for INT64_MIN!)

Add support for -INT64_MIN values in literals.

Make compiler portable (do not assume int64_t is long long int)

Add missing set overflow flag.

Fix extract_integer_value.
Now we handle signed and unsigned in different mode.
(Thanks to Andreas)

Fix typo (thanks Manuele)

Remove potential access to NULL pointer.

fix error message.

Fix array index bound check to consider uint64 indexes/limits.

Fix structure initialize.

Add check array out of bound.

Code for debugging const_value annotations in abstract syntax tree.

Fix 'overflow' detection for real64.

small bug fix.

Fix compare expression in constat folding class.

Fix extract_real (thanks Manuele), and add check for overflow.

cleaning up the code...

Fix remaining overflow checks.

remove incorrect include file.

Correctly implement MOD operation and overflow checks (still missing uint * / MOD).

Re-insert errno=0 before calling strtoXX() (thanks go to Manuele)

cosmetic changes.

Add data structure for storing overflow of constant values.

make the compiler platform independent (i.e. no longer assume sizeof(double)==8).

create extract_real_value() in absyntax_utils. NOTE: overflows not yet handled!

Update constant folding: fixing minor bug.

Fix a few bugs of previous commit.

Start constant_folding class.

little typo in last commited code
add if(is_bool_type(sym)) this->bool_type->accept(*this) in generate_c_il_c::visit(il_default_variable_c*)
to get .BOOLvar instead of .FALSEvar resp. .TRUEvar ..

Change return data type of array_dimension_iterator_c.next()

Fix SFC stage4 error.

Renamed class, remove unused code, delete allocated objects.

Start sematinc range check class.

Located variables may have other data types besides ANY_BIT.

Add verify_is_lvalue to control_variable in for_statement.

Remove useless code, and replace with assertion.

Fix bug: initialise un-initialised variable.

Delete incorrect comment.

Add some comments...

Add high level comments.

Fix comment.

Fix the previous commit: check for errors in expressions used as subscripts.

Fix data type check array subscript field.

Merge changes.

Fix parsing os TIME literals & rename the extract_integer() function.

Fix generation of output for iec2iec.

Do not compile deleted files...

Do not compile deleted files...

ReDelete files - used in old method of supporting standard functions.

Remove file (used for old method of supporting standard functions).

Add TODO list!

Delete unecessary variable.

Fix __dt_to_timespec primitive function.
Set tm_isdst = 0 to disable DayLight Savig Time.

Fix __dt_to_string primitive function.

Fix code generation about __INIT_GLOBAL_LOCATED.

Change constants into enums.

Add lvalue checking for IL function and FB invocations.

Fix comment.

Add clarifying comment.

Remove access to NULL pointer.

Make temporary fix to is_complex() method.

Fix comment. (thanks go to Manuele for pointing it put).

Stop lvalue checks after finding an error in the expression.

Remove erroneous check for S1 and R1, and add missing declrataion.

Start implement lvalue check in IL instruction.

Add lvalue check on fb invocation.

Literals are also part of expressions!

Implement check_assignment_to_expression in lvalue_check_c class.

Remove potential access to NULL pointer.

Start having nicer stage 4 error messages.

Improve usability command line under windows.

Ignore trailing EOLs when determining symbol location.
(Makes for niver error messages)

Add comment.

Fix Segmentation fault in check_assignment_to_output lvalue method.

Remove deprecated status for ANYTIME operations.

Produce similar error messages in stage2 and stage3.

Fix bug when handling code with data type errors.

Fix printing of data type errors in while and repeat statements.

Add lvalue check for non formal function invocations.

Fixing check for assingment to FOR control variables.

Moving get_var_name_c into its own file.

Fixing check for assignment to output variables.

Fixing some bugs in lvalue checking (other bugs remain - to be fixed later)

Add lvalue check class.

Determine the modifiers (CONST, REATAIN) used when declaring a variable.

Fix typo in comparison expression.

Removing code from search_varfb_instance_type_c (use search_var_instance_decl_c instead).
(Preparing to delete search_varfb_instance_type_c in the future!)

Fix bug by expanding permissible data input of search_var_instance_decl_c
(this will also prepare us for removing search_varfb_instance_type_c in the future)

Edit formating and delete unused code.