This has been filed upstream at:

    https://github.com/traviscross/mtr/issues/76

and fixed in

    https://github.com/traviscross/mtr/commit/effef18b359c78a968de28cb1090866e974bd34f

    https://github.com/traviscross/mtr/commit/0b782f6a31d999694554b670009698499e2c98cc

These changes should be available in mtr 0.87.

--- mtr-0.86/configure.ac	Tue Dec  9 03:20:57 2014

+++ mtr-0.86/configure.ac	Tue Mar 24 15:03:00 2015

@@ -20,20 +20,11 @@

 AC_CHECK_HEADERS(ncurses.h ncurses/curses.h curses.h cursesX.h sys/types.h fcntl.h)

 AC_CHECK_HEADERS(socket.h sys/socket.h sys/xti.h arpa/nameser_compat.h)

-# We don't refer to any symbols in termcap, but -lcurses on SunOS does.

-# We have to trust the linker not to mess things up... (It should not

-# pull in anything if we don't refer to anything in the lib). 

-AC_CHECK_LIB(termcap, tgetent)

-AC_CHECK_LIB(tinfo, tgetent)

+AC_SEARCH_LIBS(initscr, [ncurses curses cursesX], ,

+  AC_MSG_WARN(Building without curses display support)

+  AC_DEFINE(NO_CURSES, 1, [Define if you don't have the curses libraries available.])

+  CURSES_OBJ=)

-AC_CHECK_FUNC(initscr, , 

-  AC_CHECK_LIB(ncurses, initscr, , 

-    AC_CHECK_LIB(curses, initscr, , 

-      AC_CHECK_LIB(cursesX, initscr, , 

-	AC_MSG_WARN(Building without curses display support)

-	AC_DEFINE(NO_CURSES, 1, Define if you don't have the curses libraries available.)

-	CURSES_OBJ=))))

-

 AC_CHECK_FUNCS(attron fcntl)

 AC_CHECK_LIB(m, floor, , AC_MSG_ERROR(No math library found))

--- mtr-0.86/mtr.c	Tue Dec  9 03:20:57 2014

+++ mtr-0.86/mtr.c	Fri Mar 20 09:43:55 2015

@@ -89,7 +89,7 @@

 int   maxTTL = 30;              /* inline with traceroute */

                                 /* end ttl window stuff. */

 int remoteport = 80;            /* for TCP tracing */

-int timeout = 10 * 1000000;     /* for TCP tracing */

+int tcp_timeout = 10 * 1000000; /* for TCP tracing */

 /* default display field(defined by key in net.h) and order */

@@ -454,8 +454,8 @@

       }

       break;

     case 'Z':

-      timeout = atoi(optarg);

-      timeout *= 1000000;

+      tcp_timeout = atoi(optarg);

+      tcp_timeout *= 1000000;

       break;

     case '4':

       af = AF_INET;

--- mtr-0.86/net.c	Fri Mar 20 09:43:55 2015

+++ mtr-0.86/net.c	Fri Mar 20 09:43:55 2015

@@ -209,7 +209,7 @@

 extern int af;			/* address family of remote target */

 extern int mtrtype;		/* type of query packet used */

 extern int remoteport;          /* target port for TCP tracing */

-extern int timeout;             /* timeout for TCP connections */

+extern int tcp_timeout;		/* timeout for TCP connections */

 #ifdef SO_MARK

 extern int mark;		/* SO_MARK to set for ping packet*/

 #endif

@@ -1559,7 +1559,7 @@

     }

     if (fd > 0) {

       utime = sequence[at].time.tv_sec * 1000000L + sequence[at].time.tv_usec;

-      if (unow - utime > timeout) {

+      if (unow - utime > tcp_timeout) {

         close(fd);

         sequence[at].socket = 0;

       }