warning: deprecated conversion from string constant to 'char*'

After upgrading gcc version 4.2.3 20071014 (prerelease) (Debian 4.2.2-3),
there are a lot of warning message as

 warning: deprecated conversion from string constant to 'char*'

To add const before char*, the warning message was gone.

void    nrerror(const char *error_text);

void nrerror(const char *error_text)
  /* Numerical Recipes standard error handler */
{
  fprintf(stderr,"Numerical Recipes run-time error...\n");
  fprintf(stderr,"%s\n", error_text);
  fprintf(stderr,"...now exiting to system...\n");
  exit(1);
}

 warning:  comparison with string literal results in unspecified behaviour
 To change the way the check two string pointers,

 char *Wire_Type;
from if (Wire_Type == "scC")

to  if (!(strcmp(Wire_Type, "scC")))