Revert "Revert "external/boringssl: sync with upstream.""

This reverts commit 03bcf618b7ed811b305845461fbb5497dfe55ac3.

No changes here. trusty build was fixed with the required rules.mk changes.
diff --git a/src/crypto/bio/fd.c b/src/crypto/bio/fd.c
index 0b5baca..0b3484c 100644
--- a/src/crypto/bio/fd.c
+++ b/src/crypto/bio/fd.c
@@ -208,9 +208,9 @@
         if (ip != NULL) {
           *ip = b->num;
         }
-        return 1;
+        return b->num;
       } else {
-        ret = 0;
+        ret = -1;
       }
       break;
     case BIO_CTRL_GET_CLOSE: