I have a "NAN undeclared" error. What can I do?

Your C++ compiler does not support the C99 standard library. This is a known bug (NAN should not be used without checking for its existence before) and will be corrected. Meanwhile, use another compiler, such as the GNU C++ Compiler version 3.3 or above.

I have a conflit declaration for int getopt(). How to solve it?

The flag HAVE_DECL_GETOPT must be set. Compile with -DHAVE_DECL_GETOPT. To use this flag with the script configure, call it with:

configure CPPFLAGS='-DHAVE_DECL_GETOPT'

The expression parser behave incorrectly on some expressions

For example, expressions with weights such as a 2* (meaning "the star of a with weight 2) are not parsed correctly.

Solution: write (a 2)* instead. This problem is due to the use of LL parsing, which cannot handle expressions like the example above. This is a known misfeature, that cannot be corrected without making the code bigger and slower. Since a very readable, simple workaround exists, use it instead.