Fix various little bugs and loosen up various warnings

Change-Id: Iead48ac030290290c7c448b6f72a31380c2e8326
diff --git a/third_party/cddlib/lib-src/cddio.c b/third_party/cddlib/lib-src/cddio.c
index 58545d5..783dd1c 100644
--- a/third_party/cddlib/lib-src/cddio.c
+++ b/third_party/cddlib/lib-src/cddio.c
@@ -68,7 +68,7 @@
 
 void dd_SetWriteFileName(dd_DataFileType inputfile, dd_DataFileType outfile, char cflag, dd_RepresentationType rep)
 {
-  char *extension;
+  const char *extension;
   dd_DataFileType ifilehead="";
   int i,dotpos;
   
@@ -1931,7 +1931,7 @@
 /****************************************************************************************/
 /*  rational number (a/b) read is taken from Vinci by Benno Bueeler and Andreas Enge    */
 /****************************************************************************************/
-void dd_sread_rational_value (const char *s, mytype value)
+void dd_sread_rational_value (char *s, mytype value)
    /* reads a rational value from the specified string "s" and assigns it to "value"    */
    
 {