diff --git a/lib/libmd/Makefile b/lib/libmd/Makefile
index 727fd8621716..61bea29c96b1 100644
--- a/lib/libmd/Makefile
+++ b/lib/libmd/Makefile
@@ -42,7 +42,13 @@ CLEANFILES+=	md[245]hl.c md[245].ref md[245].3 mddriver \
 		sha0.ref sha0hl.c sha1.ref sha1hl.c shadriver \
 		sha256.ref sha256hl.c sha512.ref sha512hl.c
 
-CFLAGS+= -I${.CURDIR}
+# Define WEAK_REFS to provide weak aliases for libmd symbols
+#
+# Note that the same sources are also used internally by libcrypt,
+# in which case:
+#   * macros are used to rename symbols to libcrypt internal names
+#   * no weak aliases are generated
+CFLAGS+= -I${.CURDIR} -DWEAK_REFS
 .PATH: ${.CURDIR}/${MACHINE_ARCH} ${.CURDIR}/../../sys/crypto/sha2
 
 .if exists(${MACHINE_ARCH}/sha.S)
diff --git a/lib/libmd/md4c.c b/lib/libmd/md4c.c
index 2234c40fba96..de1a7b4acb9c 100644
--- a/lib/libmd/md4c.c
+++ b/lib/libmd/md4c.c
@@ -291,6 +291,11 @@ unsigned int len;
       (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
 }
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef MD4Init
 __weak_reference(_libmd_MD4Init, MD4Init);
 #undef MD4Update
@@ -299,3 +304,4 @@ __weak_reference(_libmd_MD4Update, MD4Update);
 __weak_reference(_libmd_MD4Pad, MD4Pad);
 #undef MD4Final
 __weak_reference(_libmd_MD4Final, MD4Final);
+#endif
diff --git a/lib/libmd/md5c.c b/lib/libmd/md5c.c
index bfbb53129cf4..6b5046416ada 100644
--- a/lib/libmd/md5c.c
+++ b/lib/libmd/md5c.c
@@ -336,6 +336,11 @@ MD5Transform (state, block)
 	memset ((void *)x, 0, sizeof (x));
 }
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef MD5Init
 __weak_reference(_libmd_MD5Init, MD5Init);
 #undef MD5Update
@@ -346,3 +351,4 @@ __weak_reference(_libmd_MD5Pad, MD5Pad);
 __weak_reference(_libmd_MD5Final, MD5Final);
 #undef MD5Transform
 __weak_reference(_libmd_MD5Transform, MD5Transform);
+#endif
diff --git a/lib/libmd/mdXhl.c b/lib/libmd/mdXhl.c
index 9db000db2f4d..62be2359c1d4 100644
--- a/lib/libmd/mdXhl.c
+++ b/lib/libmd/mdXhl.c
@@ -97,6 +97,11 @@ MDXData (const void *data, unsigned int len, char *buf)
 	return (MDXEnd(&ctx, buf));
 }
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef MDXEnd
 __weak_reference(_libmd_MDXEnd, MDXEnd);
 #undef MDXFile
@@ -105,3 +110,4 @@ __weak_reference(_libmd_MDXFile, MDXFile);
 __weak_reference(_libmd_MDXFileChunk, MDXFileChunk);
 #undef MDXData
 __weak_reference(_libmd_MDXData, MDXData);
+#endif
diff --git a/lib/libmd/rmd160c.c b/lib/libmd/rmd160c.c
index a33126f67643..5a3b78325728 100644
--- a/lib/libmd/rmd160c.c
+++ b/lib/libmd/rmd160c.c
@@ -546,6 +546,11 @@ unsigned long *l;
 	}
 #endif
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef RIPEMD160_Init
 __weak_reference(_libmd_RIPEMD160_Init, RIPEMD160_Init);
 #undef RIPEMD160_Update
@@ -558,3 +563,4 @@ __weak_reference(_libmd_RIPEMD160_Transform, RIPEMD160_Transform);
 __weak_reference(_libmd_RMD160_version, RMD160_version);
 #undef ripemd160_block
 __weak_reference(_libmd_ripemd160_block, ripemd160_block);
+#endif
diff --git a/lib/libmd/sha1c.c b/lib/libmd/sha1c.c
index ea50622a4436..93a4ff37683b 100644
--- a/lib/libmd/sha1c.c
+++ b/lib/libmd/sha1c.c
@@ -488,7 +488,11 @@ SHA_CTX *c;
 /*	memset((char *)&c,0,sizeof(c));*/
 	}
 
-
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef SHA_Init
 __weak_reference(_libmd_SHA_Init, SHA_Init);
 #undef SHA_Update
@@ -513,3 +517,4 @@ __weak_reference(_libmd_SHA1_Transform, SHA1_Transform);
 __weak_reference(_libmd_SHA1_version, SHA1_version);
 #undef sha1_block
 __weak_reference(_libmd_sha1_block, sha1_block);
+#endif
diff --git a/lib/libmd/sha256c.c b/lib/libmd/sha256c.c
index d4ab835e26bc..4227b0cfbfbb 100644
--- a/lib/libmd/sha256c.c
+++ b/lib/libmd/sha256c.c
@@ -296,6 +296,11 @@ SHA256_Final(unsigned char digest[32], SHA256_CTX * ctx)
 	memset((void *)ctx, 0, sizeof(*ctx));
 }
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef SHA256_Init
 __weak_reference(_libmd_SHA256_Init, SHA256_Init);
 #undef SHA256_Update
@@ -304,5 +309,4 @@ __weak_reference(_libmd_SHA256_Update, SHA256_Update);
 __weak_reference(_libmd_SHA256_Final, SHA256_Final);
 #undef SHA256_Transform
 __weak_reference(_libmd_SHA256_Transform, SHA256_Transform);
-#undef SHA256_version
-__weak_reference(_libmd_SHA256_version, SHA256_version);
+#endif
diff --git a/lib/libmd/sha512c.c b/lib/libmd/sha512c.c
index 5c2e2000fedc..e5e52a88442d 100644
--- a/lib/libmd/sha512c.c
+++ b/lib/libmd/sha512c.c
@@ -319,6 +319,11 @@ SHA512_Final(unsigned char digest[64], SHA512_CTX * ctx)
 	memset((void *)ctx, 0, sizeof(*ctx));
 }
 
+#ifdef WEAK_REFS
+/* When building libmd, provide weak references. Note: this is not
+   activated in the context of compiling these sources for internal
+   use in libcrypt.
+ */
 #undef SHA512_Init
 __weak_reference(_libmd_SHA512_Init, SHA512_Init);
 #undef SHA512_Update
@@ -327,5 +332,4 @@ __weak_reference(_libmd_SHA512_Update, SHA512_Update);
 __weak_reference(_libmd_SHA512_Final, SHA512_Final);
 #undef SHA512_Transform
 __weak_reference(_libmd_SHA512_Transform, SHA512_Transform);
-#undef SHA512_version
-__weak_reference(_libmd_SHA512_version, SHA512_version);
+#endif