diff --git a/configure.ac b/configure.ac
index bdbbc7a1b..8e1edbad0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1287,8 +1287,20 @@ CORE_INCS='-I$(top_srcdir)/include -I$(top_builddir)/include'
 
 # SHA1 hashing
 AC_ARG_WITH([sha1],
-            [AS_HELP_STRING([--with-sha1=libmd|libgcrypt|libcrypto|libsha1],
+            [AS_HELP_STRING([--with-sha1=libc|libmd|libgcrypt|libcrypto|libsha1],
                             [choose SHA1 implementation])])
+AC_CHECK_FUNC([SHA1Init], [HAVE_SHA1_IN_LIBC=yes])
+if test "x$with_sha1" = x && test "x$HAVE_SHA1_IN_LIBC" = xyes; then
+	with_sha1=libc
+fi
+if test "x$with_sha1" = xlibc && test "x$HAVE_SHA1_IN_LIBC" != xyes; then
+	AC_MSG_ERROR([libc requested but not found])
+fi
+if test "x$with_sha1" = xlibc; then
+	AC_DEFINE([HAVE_SHA1_IN_LIBC], [1],
+		[Use libc SHA1 functions])
+	SHA1_LIBS=""
+fi
 AC_CHECK_LIB([md], [SHA1Init], [HAVE_LIBMD=yes])
 if test "x$with_sha1" = x && test "x$HAVE_LIBMD" = xyes; then
 	with_sha1=libmd
diff --git a/include/dix-config.h.in b/include/dix-config.h.in
index ebf373392..274ce89f9 100644
--- a/include/dix-config.h.in
+++ b/include/dix-config.h.in
@@ -160,6 +160,9 @@
 /* Define to 1 if you have the <rpcsvc/dbm.h> header file. */
 #undef HAVE_RPCSVC_DBM_H
 
+/* Define to use libc SHA1 functions */
+#undef HAVE_SHA1_IN_LIBC
+
 /* Define to use libmd SHA1 functions */
 #undef HAVE_SHA1_IN_LIBMD
 
diff --git a/os/xsha1.c b/os/xsha1.c
index 94092caa7..229ce896d 100644
--- a/os/xsha1.c
+++ b/os/xsha1.c
@@ -5,7 +5,8 @@
 #include "os.h"
 #include "xsha1.h"
 
-#ifdef HAVE_SHA1_IN_LIBMD /* Use libmd for SHA1 */
+#if defined(HAVE_SHA1_IN_LIBMD)  /* Use libmd for SHA1 */ \
+	|| defined(HAVE_SHA1_IN_LIBC) /* Use libc for SHA1 */
 
 # include <sha1.h>