gcov, fix S_ISLNK

[Nathan Sidwell]

I've committed this to fix windows and other non-modern posix systems.

nathan

2011-11-14  Nathan Sidwell  <nat...@acm.org>

        * gcov.c (canonicalize_name): Protect use of S_ISLNK.

Index: gcov.c
===================================================================
--- gcov.c      (revision 181347)
+++ gcov.c      (working copy)
@@ -1688,13 +1688,22 @@ canonicalize_name (const char *name)
        {
          /* '..', we can only elide it and the previous directory, if
             we're not a symlink.  */
-         struct stat buf;
-         
+         struct stat ATTRIBUTE_UNUSED buf;
+
          *ptr = 0;
-         if (dd_base == ptr || stat (result, &buf) || S_ISLNK (buf.st_mode))
+         if (dd_base == ptr
+#if defined (S_ISLNK)
+             /* S_ISLNK is not POSIX.1-1996.  */
+             || stat (result, &buf) || S_ISLNK (buf.st_mode)
+#endif
+             )
            {
              /* Cannot elide, or unreadable or a symlink.  */
              dd_base = ptr + 2 + slash;