d: Use filename_ncmp instead of strncmp

gcc/d/ChangeLog:

	* d-incpath.cc (prefixed_path): Use filename_ncmp instead of strncmp.

gcc/d/d-incpath.cc

@@ -30,11 +30,9 @@ along with GCC; see the file COPYING3.  If not see
 static char *
 prefixed_path (const char *path, const char *iprefix)
 {
-  size_t len;
-
-  if (cpp_relocated () && (len = cpp_PREFIX_len) != 0)
+  if (cpp_relocated () && cpp_PREFIX_len != 0)
   {
-    if (!strncmp (path, cpp_PREFIX, len))
+    if (!filename_ncmp (path, cpp_PREFIX, cpp_PREFIX_len))
       {
 	static const char *relocated_prefix;
 	/* If this path starts with the configure-time prefix,
@@ -52,14 +50,14 @@ prefixed_path (const char *path, const char *iprefix)
 	    free (dummy);
 	  }
 
-	return concat (relocated_prefix, path + len, NULL);
+	return concat (relocated_prefix, path + cpp_PREFIX_len, NULL);
       }
   }
 
-  if (iprefix && (len = cpp_GCC_INCLUDE_DIR_len) != 0)
+  if (iprefix && cpp_GCC_INCLUDE_DIR_len != 0)
     {
-      if (!strncmp (path, cpp_GCC_INCLUDE_DIR, len))
-	return concat (iprefix, path + len, NULL);
+      if (!filename_ncmp (path, cpp_GCC_INCLUDE_DIR, cpp_GCC_INCLUDE_DIR_len))
+	return concat (iprefix, path + cpp_GCC_INCLUDE_DIR_len, NULL);
     }
 
   return xstrdup (path);