Update chain building function. Don't clear verification errors from the error queue unless SSL_BUILD_CHAIN_FLAG_CLEAR_ERROR is set. If errors occur during verification and SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR is set return 2 so applications can issue warnings. (cherry picked from commit 2dd6976f6d02f98b30c376951ac38f780a86b3b5)

diff --git a/ssl/ssl.h b/ssl/ssl.h
index c6cd6a9..27dcb09 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h

@@ -791,6 +791,8 @@
 #define SSL_BUILD_CHAIN_FLAG_CHECK		0x4
 /* Ignore verification errors */
 #define SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR	0x8
+/* Clear verification errors from queue */
+#define SSL_BUILD_CHAIN_FLAG_CLEAR_ERROR	0x10
 
 /* Flags returned by SSL_check_chain */
 /* Certificate can be used with this session */

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 09ea611..3ad0f8b 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c

@@ -1247,8 +1247,10 @@
 	i = X509_verify_cert(&xs_ctx);
 	if (i <= 0 && flags & SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR)
 		{
-		ERR_clear_error();
+		if (flags & SSL_BUILD_CHAIN_FLAG_CLEAR_ERROR)
+			ERR_clear_error();
 		i = 1;
+		rv = 2;
 		}
 	if (i > 0)
 		chain = X509_STORE_CTX_get1_chain(&xs_ctx);
@@ -1283,7 +1285,8 @@
 			}
 		}
 	cpk->chain = chain;
-	rv = 1;
+	if (rv == 0)
+		rv = 1;
 	err:
 	if (flags & SSL_BUILD_CHAIN_FLAG_CHECK)
 		X509_STORE_free(chain_store);