Merge branch 'ew/keepalive' into maint

* ew/keepalive:
enable SO_KEEPALIVE for connected TCP sockets

diff --cc connect.c
index 51990fa0cb300a95b125b0727f10133961d0167b,d725b1794f4a6d272a0cc649f57d99453255f8cc..d0f59ef0deebff3967c0b054f2f998dfb3ab5b00
--- 1/connect.c
--- 2/connect.c
+++ b/connect.c
@@@ -310,8 -324,10 +321,10 @@@ static int git_tcp_connect_sock(char *h
        }
  
        if (sockfd < 0)
 -              die("unable to connect a socket (%s)", strerror(saved_errno));
 +              die("unable to connect to %s:\n%s", host, error_message.buf);
  
+       enable_keepalive(sockfd);
+ 
        if (flags & CONNECT_VERBOSE)
                fprintf(stderr, "done.\n");