Fix shared library build on OS X.

It seems OS X actually cares about symbol resolution and dependencies
when you create a dylib. Probably because they do two-level name
resolution.

(Obligatory disclaimer: BoringSSL does not have a stable ABI and is thus
not suitable for a traditional system-wide library.)

BUG=539603

Change-Id: Ic26c4ad23840fe6c1f4825c44671e74dd2e33870
Reviewed-on: https://boringssl-review.googlesource.com/6131
Reviewed-by: Adam Langley <alangley@gmail.com>
diff --git a/include/openssl/des.h b/include/openssl/des.h
index f9db62d..2b8dd0f 100644
--- a/include/openssl/des.h
+++ b/include/openssl/des.h
@@ -157,6 +157,19 @@
                                          DES_cblock *ivec, int enc);
 
 
+/* Private functions.
+ *
+ * These functions are only exported for use in |decrepit|. */
+
+OPENSSL_EXPORT void DES_decrypt3(uint32_t *data, const DES_key_schedule *ks1,
+                                 const DES_key_schedule *ks2,
+                                 const DES_key_schedule *ks3);
+
+OPENSSL_EXPORT void DES_encrypt3(uint32_t *data, const DES_key_schedule *ks1,
+                                 const DES_key_schedule *ks2,
+                                 const DES_key_schedule *ks3);
+
+
 #if defined(__cplusplus)
 }  /* extern C */
 #endif