Mark cdiLibraryVersion result read-only.

src/cdi.h

@@ -226,7 +226,7 @@ char   *cdiStringError(int cdiErrno);
 
 void    cdiDebug(int debug);
 
-char   *cdiLibraryVersion(void);
+const char *cdiLibraryVersion(void);
 void    cdiPrintVersion(void);
 
 int     cdiHaveFiletype(int filetype);

src/version.c

@@ -7,7 +7,7 @@
  */
 
 #if defined (VERSION)
-   static char cdi_libvers[] = VERSION " of "__DATE__" "__TIME__;
+   static const char cdi_libvers[] = VERSION " of "__DATE__" "__TIME__;
 #else
 #  error "VERSION undefined"
 #endif
@@ -15,12 +15,12 @@
 #if defined(__cplusplus)
 extern "C" {
 #endif
-char *cdiLibraryVersion(void);
+const char *cdiLibraryVersion(void);
 #if defined(__cplusplus)
 }
 #endif
 */
-char *cdiLibraryVersion(void)
+const char *cdiLibraryVersion(void)
 {
   return (cdi_libvers);
 }