Implement Mario's suggestions:
- Clean up code replace merge algorithm with a function.
- Fix for_statement setting control variable to not a constant.
- Fix for_statement checking BY expression to get correct value for optimization
branch.

Thanks Mario.

Fix constant_folding missing call. [Bug found by Mario.]

Fix divide by 0 bug.

merge

Fix CPPFLAGS Makefile.am for all stage4.

Remove redundant class for get variable name.

Fix constant propagation alg. in for statement like Mario suggestion.

Add note about How Constant Folding class is extended with a implementation constant propagation algorithm
by Mario de Sousa.

Add constant propagation algorithm for loop cycles.

Update symbol_c::first_file/last_file entries in list_c::add_element()

moved class to obtain datatype name (in char *) to get_datatype_info_c

merge

Fix comment about meet semilattice rules.

Complete fix initialize const_value.

Start to implement constant propagation algorithm.

Fix const_value field initialized.

Remove Ambiguous enumerate value in enum conversion functions.

Fix enum conversion function to string.

Fix struct generic_function_call_t initialize style.

Merge with Mario's changes.

Merge with Mario's repository.

Fix warning about call fprintf without format string.

merge

Remove Ambiguous enumerate value in enum conversion functions.

Fix enum conversion function to string.

Fix struct generic_function_call_t initialize style.

Small code cleanup.

Allow bison to ask for an END_OF_INPUT token multiple times!

Protect against redefining macros

merge

Fix flag to enable conversion functions.

Code cleanup: move tracking functions to flex.

Insert the auto generated enum datatype conversion functions after the TYPE...END_TYPE, instead of at the end of input file.

merge

Set ENO to false when conversion function fails.

Fix typo in functionDataType array.

Add files missing from a few commits ago...

merge

Refix automake files.

Add some comments to argument new code.

Start to change code like Mario suggestions.

Create functionDataType array in derived_conversion_functions_c.

Add conversion functions option.

Start enumerate conversion functions.

merge

Be sure to not redefine TRUE and FALSE macros.

merge

Removed unused __attribute__((__packed__)) only gcc compatible.

Protect IEC_STD_LIB.H header agaist multi-include problems.

merge

Start to move enumeration declaration checking to its own class.

Fix comments and code alignment

Fix warnings previous change introduced when compiling with gcc.

Fix some important clang++ warnings.

Allow use of type#value syntax when defining default initial value inside a TYPE..END_TYPE declaration.

Do datatype verification of fully qualified enumerated values (e.g. ENUMTYPE#enumconst)

Add datatype checking of enumeration data type declarations.

Print const values of symbol.

Fix code generation of enum value constants (this is a temporary fix - it will be followed by a code cleanup).

Fix bug in datatype checking of enumerated datatypes delcarations.