Implement conditional compilation

Implement conditional compilation

Before this commit, compilation would stop at file parsing.c
with error (warning + -Werror) caused by -Wtype-limits.
Conditional compilation is added so that the offending if statement
is not present, when not needed.

The #if directive could have only been set up around the problematic
if statement. The 42 Norm however forbids using macros anywhere but
the global scope.

This made me write the the affected functions twice, which then broke
the 5 function limit per .c file. Hence this commit is quite large
for such a small change.