csync_exclude: Fix compile

csync_exclude.cpp:428:17: error: assigning to 'char *' from incompatible type 'const char *'
        bname = path;
                ^~~~

The C library's strrchr always return 'char*'
Only the C++'s std::strrchr has two overloads

src/csync/csync_exclude.cpp

@@ -421,7 +421,7 @@ CSYNC_EXCLUDE_TYPE ExcludedFiles::traversalPatternMatch(const char *path, int fi
     // Check the bname part of the path to see whether the full
     // regex should be run.
 
-    auto bname = strrchr(path, '/');
+    const char *bname = strrchr(path, '/');
     if (bname) {
         bname += 1; // don't include the /
     } else {