const char *system_path(const char *path)
 {
+#ifdef RUNTIME_PREFIX
+       static const char *prefix;
+#else
        static const char *prefix = PREFIX;
+#endif
        struct strbuf d = STRBUF_INIT;
 
        if (is_absolute_path(path))
                return path;
 
+#ifdef RUNTIME_PREFIX
+       assert(argv0_path);
+       assert(is_absolute_path(argv0_path));
+
+       if (!prefix &&
+           !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
+           !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
+           !(prefix = strip_path_suffix(argv0_path, "git"))) {
+               prefix = PREFIX;
+               fprintf(stderr, "RUNTIME_PREFIX requested, "
+                               "but prefix computation failed.  "
+                               "Using static fallback '%s'.\n", prefix);
+       }
+#endif
+
        strbuf_addf(&d, "%s/%s", prefix, path);
        path = strbuf_detach(&d, NULL);
        return path;