+#if ZLIB_VERNUM < 0x1200
+#define deflateBound(c,s) ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
+#endif
+
+#ifdef DT_UNKNOWN
+#define DTYPE(de) ((de)->d_type)
+#else
+#define DT_UNKNOWN 0
+#define DT_DIR 1
+#define DT_REG 2
+#define DT_LNK 3
+#define DTYPE(de) DT_UNKNOWN
+#endif
+
+/*
+ * Environment variables transition.
+ * We accept older names for now but warn.
+ */
+extern char *gitenv_bc(const char *);
+#define gitenv(e) (getenv(e) ? : gitenv_bc(e))
+