Readd MD4.

Sadly this is needed by wpa_supplicant for NTLM hashes.

Change-Id: I1c362c676a11ee01f301ff6fbd33d0669396ea23
Reviewed-on: https://boringssl-review.googlesource.com/1620
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/base.h b/include/openssl/base.h
index d79d63f..bee4030 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -184,6 +184,7 @@
 typedef struct evp_pkey_method_st EVP_PKEY_METHOD;
 typedef struct evp_pkey_st EVP_PKEY;
 typedef struct hmac_ctx_st HMAC_CTX;
+typedef struct md4_state_st MD4_CTX;
 typedef struct md5_state_st MD5_CTX;
 typedef struct pkcs8_priv_key_info_st PKCS8_PRIV_KEY_INFO;
 typedef struct rand_meth_st RAND_METHOD;
diff --git a/include/openssl/digest.h b/include/openssl/digest.h
index 76d6677..291a548 100644
--- a/include/openssl/digest.h
+++ b/include/openssl/digest.h
@@ -76,6 +76,7 @@
  * The following functions return |EVP_MD| objects that implement the named hash
  * function. */
 
+OPENSSL_EXPORT const EVP_MD *EVP_md4(void);
 OPENSSL_EXPORT const EVP_MD *EVP_md5(void);
 OPENSSL_EXPORT const EVP_MD *EVP_sha1(void);
 OPENSSL_EXPORT const EVP_MD *EVP_sha224(void);
diff --git a/include/openssl/md4.h b/include/openssl/md4.h
new file mode 100644
index 0000000..c67ad97
--- /dev/null
+++ b/include/openssl/md4.h
@@ -0,0 +1,105 @@
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.] */
+
+#ifndef OPENSSL_HEADER_MD4_H
+#define OPENSSL_HEADER_MD4_H
+
+#include <openssl/base.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+/* MD4. */
+
+/* MD4_CBLOCK is the block size of MD4. */
+#define MD4_CBLOCK 64
+
+/* MD4_DIGEST_LENGTH is the length of an MD4 digest. */
+#define MD4_DIGEST_LENGTH 16
+
+/* MD41_Init initialises |md4| and returns one. */
+OPENSSL_EXPORT int MD4_Init(MD4_CTX *md4);
+
+/* MD4_Update adds |len| bytes from |data| to |md4| and returns one. */
+OPENSSL_EXPORT int MD4_Update(MD4_CTX *md4, const void *data, size_t len);
+
+/* MD4_Final adds the final padding to |md4| and writes the resulting digest to
+ * |md|, which must have at least |MD4_DIGEST_LENGTH| bytes of space. It
+ * returns one. */
+OPENSSL_EXPORT int MD4_Final(uint8_t *md, MD4_CTX *md4);
+
+/* MD4 writes the digest of |len| bytes from |data| to |out| and returns |out|.
+ * There must be at least |MD4_DIGEST_LENGTH| bytes of space in |out|. */
+OPENSSL_EXPORT uint8_t *MD4(const uint8_t *data, size_t len, uint8_t *out);
+
+/* MD4_Transform is a low-level function that performs a single, MD4 block
+ * transformation using the state from |md4| and 64 bytes from |block|. */
+OPENSSL_EXPORT void MD4_Transform(MD4_CTX *md4, const uint8_t *block);
+
+typedef struct md4_state_st {
+  uint32_t A, B, C, D;
+  uint32_t Nl, Nh;
+  uint32_t data[16];
+  unsigned int num;
+} MD4_CTX;
+
+
+#if defined(__cplusplus)
+}  /* extern C */
+#endif
+
+#endif  /* OPENSSL_HEADER_MD4_H */
diff --git a/include/openssl/md5.h b/include/openssl/md5.h
index dc800c0..efedc98 100644
--- a/include/openssl/md5.h
+++ b/include/openssl/md5.h
@@ -72,7 +72,7 @@
 /* MD5_DIGEST_LENGTH is the length of an MD5 digest. */
 #define MD5_DIGEST_LENGTH 16
 
-/* MD51_Init initialises |md5| and returns 1. */
+/* MD51_Init initialises |md5| and returns one. */
 OPENSSL_EXPORT int MD5_Init(MD5_CTX *md5);
 
 /* MD5_Update adds |len| bytes from |data| to |md5| and returns one. */
diff --git a/include/openssl/opensslfeatures.h b/include/openssl/opensslfeatures.h
index 6026a4b..4f5cb31 100644
--- a/include/openssl/opensslfeatures.h
+++ b/include/openssl/opensslfeatures.h
@@ -37,7 +37,6 @@
 #define OPENSSL_NO_JPAKE
 #define OPENSSL_NO_KRB5
 #define OPENSSL_NO_MD2
-#define OPENSSL_NO_MD4
 #define OPENSSL_NO_MDC2
 #define OPENSSL_NO_OCSP
 #define OPENSSL_NO_RC2