Backported git commit 37ca949e462a7608572f653848b5a7554964fd53
"Fix more hardcoded termlen"
See bug 585696.

diff -Naurd screen-4.3.1.orig/attacher.c screen-4.3.1/attacher.c
--- screen-4.3.1.orig/attacher.c	2015-06-29 00:22:55.000000000 +0300
+++ screen-4.3.1/attacher.c	2016-06-12 17:00:41.091761944 +0300
@@ -364,8 +364,8 @@
     }
 #endif
   ASSERT(how == MSG_ATTACH || how == MSG_CONT);
-  strncpy(m.m.attach.envterm, attach_term, sizeof(m.m.attach.envterm) - 1);
-  m.m.attach.envterm[sizeof(m.m.attach.envterm) - 1] = 0;
+  strncpy(m.m.attach.envterm, attach_term, MAXTERMLEN);
+  m.m.attach.envterm[MAXTERMLEN] = 0;
   debug1("attach: sending %d bytes... ", (int)sizeof(m));
 
   strncpy(m.m.attach.auser, LoginName, sizeof(m.m.attach.auser) - 1); 
diff -Naurd screen-4.3.1.orig/display.c screen-4.3.1/display.c
--- screen-4.3.1.orig/display.c	2015-06-29 00:22:55.000000000 +0300
+++ screen-4.3.1/display.c	2016-06-12 17:03:00.196561319 +0300
@@ -309,8 +309,8 @@
 
   strncpy(D_usertty, utty, sizeof(D_usertty) - 1);
   D_usertty[sizeof(D_usertty) - 1] = 0;
-  strncpy(D_termname, term, sizeof(D_termname) - 1);
-  D_termname[sizeof(D_termname) - 1] = 0;
+  strncpy(D_termname, term, MAXTERMLEN);
+  D_termname[MAXTERMLEN] = 0;
   D_user = *u;
   D_processinput = ProcessInput;
   D_mousetrack = defmousetrack;
@@ -3725,14 +3725,14 @@
   char *m;
   int pid;
   int slave = -1;
-  char termname[30];
+  char termname[MAXTERMLEN + 6];
 #ifndef TIOCSWINSZ
   char libuf[20], cobuf[20];
 #endif
   char **np;
 
   strcpy(termname, "TERM=");
-  strncpy(termname + 5, D_termname, sizeof(termname) - 6);
+  strncpy(termname + 5, D_termname, MAXTERMLEN - 6);
   termname[sizeof(termname) - 1] = 0;
   KillBlanker();
   D_blankerpid = -1;
diff -Naurd screen-4.3.1.orig/process.c screen-4.3.1/process.c
--- screen-4.3.1.orig/process.c	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/process.c	2016-06-12 17:04:37.999014093 +0300
@@ -2672,13 +2672,14 @@
       s = NULL;
       if (ParseSaveStr(act, &s))
 	break;
-      if (strlen(s) >= MAXTERMLEN)
+      if (strlen(s) > MAXTERMLEN)
 	{
 	  OutputMsg(0, "%s: term: argument too long ( < %d)", rc_name, MAXTERMLEN);
 	  free(s);
 	  break;
 	}
-      strcpy(screenterm, s);
+      strncpy(screenterm, s, MAXTERMLEN);
+      screenterm[MAXTERMLEN] = '\0';
       free(s);
       debug1("screenterm set to %s\n", screenterm);
       MakeTermcap((display == 0));
diff -Naurd screen-4.3.1.orig/screen.c screen-4.3.1/screen.c
--- screen-4.3.1.orig/screen.c	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/screen.c	2016-06-12 17:18:35.887758770 +0300
@@ -507,7 +507,8 @@
 #endif
   nwin = nwin_undef;
   nwin_options = nwin_undef;
-  strcpy(screenterm, "screen");
+  strncpy(screenterm, "screen", MAXTERMLEN);
+  screenterm[MAXTERMLEN] = '\0';
 #ifdef BUILTIN_TELNET
   af = AF_UNSPEC;
 #endif
@@ -689,8 +690,10 @@
 		case 'T':
 		  if (--ac == 0)
 		    exit_with_usage(myname, "Specify terminal-type with -T", NULL);
-		  if (strlen(*++av) < 20)
-		    strcpy(screenterm, *av);
+		  if (strlen(*++av) < MAXTERMLEN) {
+		    strncpy(screenterm, *av, MAXTERMLEN);
+            screenterm[MAXTERMLEN] = '\0';
+          }
 		  else
 		    Panic(0, "-T: terminal name too long. (max. 20 char)");
 		  nwin_options.term = screenterm;
@@ -1034,7 +1037,7 @@
 
       if ((attach_term = getenv("TERM")) == 0 || *attach_term == 0)
 	Panic(0, "Please set a terminal type.");
-      if (strlen(attach_term) > sizeof(D_termname) - 1)
+      if (strlen(attach_term) > MAXTERMLEN)
 	Panic(0, "$TERM too long - sorry.");
       GetTTY(0, &attach_Mode);
 #ifdef DEBUGGGGGGGGGGGGGGG
diff -Naurd screen-4.3.1.orig/screen.h screen-4.3.1/screen.h
--- screen-4.3.1.orig/screen.h	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/screen.h	2016-06-12 17:19:07.821253585 +0300
@@ -204,7 +204,7 @@
 	  int nargs;
 	  char line[MAXPATHLEN];
 	  char dir[MAXPATHLEN];
-	  char screenterm[MAXTERMLEN];	/* is screen really "screen" ? */
+	  char screenterm[MAXTERMLEN + 1];	/* is screen really "screen" ? */
 	}
       create;
       struct
diff -Naurd screen-4.3.1.orig/socket.c screen-4.3.1/socket.c
--- screen-4.3.1.orig/socket.c	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/socket.c	2016-06-12 17:20:01.577403167 +0300
@@ -695,8 +695,8 @@
       return;
     }
   if (nwin->term != nwin_undef.term)
-    strncpy(m.m.create.screenterm, nwin->term, 19);
-  m.m.create.screenterm[19] = '\0';
+    strncpy(m.m.create.screenterm, nwin->term, MAXTERMLEN);
+  m.m.create.screenterm[MAXTERMLEN] = '\0';
   m.protocol_revision = MSG_REVISION;
   debug1("SendCreateMsg writing '%s'\n", m.m.create.line);
   if (write(s, (char *) &m, sizeof m) != sizeof m)
diff -Naurd screen-4.3.1.orig/termcap.c screen-4.3.1/termcap.c
--- screen-4.3.1.orig/termcap.c	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/termcap.c	2016-06-12 17:21:40.297841419 +0300
@@ -72,7 +72,7 @@
 static int Termcaplen;
 static int tcLineLen;
 char Term[MAXSTR+5];		/* +5: "TERM=" */
-char screenterm[20];		/* new $TERM, usually "screen" */
+char screenterm[MAXTERMLEN + 1];    /* new $TERM, usually "screen" */
 
 char *extra_incap, *extra_outcap;
 
@@ -883,7 +883,8 @@
   if (*screenterm == '\0' || strlen(screenterm) > MAXSTR - 3)
     {
       debug("MakeTermcap sets screenterm=screen\n");
-      strcpy(screenterm, "screen");
+      strncpy(screenterm, "screen", MAXTERMLEN);
+      screenterm[MAXTERMLEN] = '\0';
     }
 #if 0
   found = 1;
diff -Naurd screen-4.3.1.orig/window.c screen-4.3.1/window.c
--- screen-4.3.1.orig/window.c	2015-06-29 00:22:56.000000000 +0300
+++ screen-4.3.1/window.c	2016-06-12 17:22:53.174688514 +0300
@@ -1438,7 +1438,7 @@
       NewEnv[4] = shellbuf;
       debug1("ForkWindow: NewEnv[4] = '%s'\n", shellbuf);
       if (win->w_term && *win->w_term && strcmp(screenterm, win->w_term) &&
-	  (strlen(win->w_term) < 20))
+	  (strlen(win->w_term) < MAXTERMLEN))
 	{
 	  char *s1, *s2, tl;