A autoconf checks for libz and libdl when OpenSSL is enabled to allow for static linking of OpenSSL (via CFLAGS=-static).
diff --git a/configure b/configure
index df051da..cf6b986 100755
--- a/configure
+++ b/configure
@@ -4838,6 +4838,106 @@
LDFLAGS="$LDFLAGS $(pkg-config --libs openssl)";
CFLAGS="$CFLAGS $(pkg-config --cflags openssl)";
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+$as_echo_n "checking for dlopen in -ldl... " >&6; }
+if ${ac_cv_lib_dl_dlopen+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen ();
+int
+main ()
+{
+return dlopen ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_dl_dlopen=yes
+else
+ ac_cv_lib_dl_dlopen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+$as_echo "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBDL 1
+_ACEOF
+
+ LIBS="-ldl $LIBS"
+
+else
+ { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "can't find libdl
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for inflate in -lz" >&5
+$as_echo_n "checking for inflate in -lz... " >&6; }
+if ${ac_cv_lib_z_inflate+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char inflate ();
+int
+main ()
+{
+return inflate ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_z_inflate=yes
+else
+ ac_cv_lib_z_inflate=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_z_inflate" >&5
+$as_echo "$ac_cv_lib_z_inflate" >&6; }
+if test "x$ac_cv_lib_z_inflate" = xyes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBZ 1
+_ACEOF
+
+ LIBS="-lz $LIBS"
+
+else
+ { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "can't find libz
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for EVP_EncryptInit in -lcrypto" >&5
$as_echo_n "checking for EVP_EncryptInit in -lcrypto... " >&6; }
if ${ac_cv_lib_crypto_EVP_EncryptInit+:} false; then :