Index: libesmtp-1.0.6/ntlm/ntlmdes.c
===================================================================
--- libesmtp-1.0.6.orig/ntlm/ntlmdes.c
+++ libesmtp-1.0.6/ntlm/ntlmdes.c
@@ -26,9 +26,21 @@
 #include <ctype.h>
 #include <openssl/des.h>
 #include <openssl/md4.h>
+#include <openssl/opensslv.h>
 
 #include "ntlm.h"
 
+/* OpenSSL 1.1 compat shim */
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+#  define des_cblock DES_cblock
+#  define const_des_cblock const_DES_cblock
+#  define des_key_schedule DES_key_schedule
+#  define des_set_odd_parity(k) DES_set_odd_parity((k))
+#  define des_set_key(k,ks) DES_set_key((k),&(ks))
+#  define des_ecb_encrypt(i,o,k,e) DES_ecb_encrypt((i),(o),&(k),(e))
+
+#endif
+
 static void
 lm_deshash (void *result, const_des_cblock *iv, const void *secret)
 {
Index: libesmtp-1.0.6/configure.ac
===================================================================
--- libesmtp-1.0.6.orig/configure.ac
+++ libesmtp-1.0.6/configure.ac
@@ -303,17 +303,8 @@ if test x$with_openssl != xno ; then
 	)
 fi
 if test x$with_openssl != xno ; then
-	AC_CHECK_LIB(ssl, SSL_library_init, [
-				with_openssl=yes
-				LIBS="-lssl -lcrypto $LIBS"
-		     ], [
-		     if test x"$with_openssl" = xyes ; then
-				AC_MSG_ERROR([cannot find the ssl library])
-		     else
-				with_openssl=no
-		     fi],
-		     -lcrypto
-	)
+PKG_CHECK_MODULES([SSL], [libssl])
+PKG_CHECK_MODULES([CRYPTO], [libcrypto])
 fi
 
 dnl #########################################################################
Index: libesmtp-1.0.6/ntlm/Makefile.am
===================================================================
--- libesmtp-1.0.6.orig/ntlm/Makefile.am
+++ libesmtp-1.0.6/ntlm/Makefile.am
@@ -8,4 +8,5 @@ AM_CFLAGS = @CFLAGS@ @EXTRA_CFLAGS@
 lib_LTLIBRARIES = sasl-ntlm.la
 
 sasl_ntlm_la_SOURCES = client-ntlm.c ntlmdes.c ntlmstruct.c ntlm.h
-sasl_ntlm_la_LDFLAGS = -module -avoid-version @NTLM_LIBS@
+sasl_ntlm_la_LDFLAGS = -no-undefined -module -shared -avoid-version -export-dynamic
+sasl_ntlm_la_LIBADD = $(CRYPTO_LIBS)
Index: libesmtp-1.0.6/Makefile.am
===================================================================
--- libesmtp-1.0.6.orig/Makefile.am
+++ libesmtp-1.0.6/Makefile.am
@@ -18,9 +18,9 @@ libesmtp_la_SOURCES = auth-client.c base
 		      libesmtp-private.h message-source.h protocol-states.h \
 		      protocol.h rfc2822date.h siobuf.h tokens.h \
 		      getaddrinfo.h gethostbyname.h missing.h
-libesmtp_la_LIBADD = @LTLIBOBJS@
+libesmtp_la_LIBADD = @LTLIBOBJS@ $(CRYPTO_LIBS) $(SSL_LIBS)
 
-libesmtp_la_LDFLAGS = -export-dynamic \
+libesmtp_la_LDFLAGS = -export-dynamic -Wl,--no-undefined \
 		      -version-info $(LIBESMTP_VERSION)
 
 include_HEADERS = libesmtp.h auth-client.h auth-plugin.h