Add option to disable Rock-Ridge support --disable-rock

Add IS_ISSOCK() or S_ISLNK() macros for Rock-Ridge when environment
doesn't have it, e.g. MSYS 1.0.10 with MinGW 3.4.2.

Go over --enable settings. --disable-cpp-progs now works.

Require libcddb 1.0.1 or better

include/cdio/rock.h

@@ -1,5 +1,5 @@
 /*
-    $Id: rock.h,v 1.9 2005/08/27 14:25:58 rocky Exp $
+    $Id: rock.h,v 1.10 2005/09/15 06:36:01 rocky Exp $
 
     Copyright (C) 2005 Rocky Bernstein <rocky@panix.com>
 
@@ -37,6 +37,16 @@
 extern "C" {
 #endif /* __cplusplus */
 
+/* MSYS 1.0.10 with MinGW 3.4.2 (and perhaps others) don't have
+   S_ISSOCK() or S_ISLNK() macros, so we'll roll our own. */
+#if !defined(HAVE_S_ISSOCK) && !defined(S_ISSOCK)
+#define S_ISSOCK(st_mode) ((((st_mode)) & 0170000) == (0140000))
+#endif
+
+#if !defined(HAVE_S_ISLNK) && !defined(S_ISLNK)
+#define S_ISLNK(st_mode) ((((st_mode)) & 0170000) == (0010000))
+#endif
+
 /*! An enumeration for some of the ISO_ROCK_* #defines below. This isn't
   really an enumeration one would really use in a program it is to
   be helpful in debuggers where wants just to refer to the ISO_ROCK_*