First cut at IBM TSS support, mostly copied from James's tpm2 engine.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

configure.ac

@@ -492,7 +492,7 @@ case "$ssl_library" in
 			      AC_SUBST(TPM2_LIBS, ['$(TASN1_LIBS) $(TSS2_ESYS_LIBS)'])
 			      tss2lib=tss2-esys],
 			     [:])
-	   if test "$tss2lib" = "xxNOTIMPLEMENTEDYETxx"; then
+	   if test "$tss2lib" = ""; then
 	       AC_CHECK_LIB([tss], [TSS_Create], [tss2inc=tss2
 						  tss2lib=tss],
 			    AC_CHECK_LIB([ibmtss], [TSS_Create], [tss2inc=ibmtss

gnutls_tpm2_esys.c

@@ -510,7 +510,7 @@ int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, g
 					   &vpninfo->tpm2->pub);
 	if (r) {
 		vpn_progress(vpninfo, PRG_ERR,
-			     _("Failed to import TPM2 private key data: 0x%x\n"),
+			     _("Failed to import TPM2 public key data: 0x%x\n"),
 			     r);
 		goto err_out;
 	}