+/*
+ * Normalize "path", prepending the "prefix" for relative paths. If
+ * remaining_prefix is not NULL, return the actual prefix still
+ * remains in the path. For example, prefix = sub1/sub2/ and path is
+ *
+ * foo -> sub1/sub2/foo (full prefix)
+ * ../foo -> sub1/foo (remaining prefix is sub1/)
+ * ../../bar -> bar (no remaining prefix)
+ * ../../sub1/sub2/foo -> sub1/sub2/foo (but no remaining prefix)
+ * `pwd`/../bar -> sub1/bar (no remaining prefix)
+ */
+char *prefix_path_gently(const char *prefix, int len,
+ int *remaining_prefix, const char *path)