Silence warnings produced by passing a string literal to a 'char*':

cddio.C: In function ‘void SetWriteFileName(char*, char, char*)’:
cddio.C:103:20: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]
           extension=".ine"; break;     /* output file for ine data */

--- a/cdd.h
+++ b/cdd.h
@@ -185,8 +185,8 @@
 extern int output_digits;  /* Float digits for output.  Does not affect the computation. */
 
 void SetInputFile(boolean *);
-void SetWriteFileName(DataFileType, char, char *);
-void SetReadFileName(DataFileType, char, char *);
+void SetWriteFileName(DataFileType, char, const char *);
+void SetReadFileName(DataFileType, char, const char *);
 
 myTYPE FABS(myTYPE);
 void SetNumberType(string);
--- a/cddio.C
+++ b/cddio.C
@@ -90,10 +90,10 @@
   }
 }
 
-void SetWriteFileName(DataFileType fname, char cflag, char *fscript)
+void SetWriteFileName(DataFileType fname, char cflag, const char *fscript)
 {
   boolean quit=False;
-  char *extension;
+  const char *extension;
   DataFileType newname;
   
   switch (cflag) {
@@ -192,10 +192,10 @@
   if (DynamicWriteOn) printf("Open %s file %s.\n",fscript,fname);
 }
 
-void SetReadFileName(DataFileType fname, char cflag, char *fscript)
+void SetReadFileName(DataFileType fname, char cflag, const char *fscript)
 {
   boolean quit=False;
-  char *extension;
+  const char *extension;
   DataFileType newname;
   
   switch (cflag) {