`-Wwrite-strings'
     When compiling C, give string constants the type `const
     char[LENGTH]' so that copying the address of one into a
     non-`const' `char *' pointer will get a warning; when compiling
     C++, warn about the deprecated conversion from string constants to
     `char *'.  These warnings will help you find at compile time code
     that can try to write into a string constant, but only if you have
     been very careful about using `const' in declarations and
     prototypes.  Otherwise, it will just be a nuisance; this is why we
     did not make `-Wall' request these warnings.