Hardcode the terminals which accept "set window title"

terminfo does not have reliable information on this, so we hardcode a whitelist
of terminal type prefixes.  This is the list from Debian's default screenrc,
plus "screen" itself (which also covers tmux).

Closes #172.
Closes #191.

src/terminal/terminaldisplay.cc

@@ -42,9 +42,10 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
   }
 
   /* has icon name or window title changed? */
-  if ( (!initialized)
+  if ( has_title &&
+       ( (!initialized)
          || (f.get_icon_name() != frame.last_frame.get_icon_name())
-       || (f.get_window_title() != frame.last_frame.get_window_title()) ) {
+         || (f.get_window_title() != frame.last_frame.get_window_title()) ) ) {
       /* set icon name and window title */
     if ( f.get_icon_name() == f.get_window_title() ) {
       /* write combined Icon Name and Window Title */

src/terminal/terminaldisplay.h

@@ -56,6 +56,8 @@ namespace Terminal {
 
     bool has_bce; /* erases result in cell filled with background color */
 
+    bool has_title; /* supports window title and icon name */
+
     int posterize_colors; /* downsample input colors >8 to [0..7] */
 
     void put_cell( bool initialized, FrameState &frame, const Framebuffer &f ) const;

src/terminal/terminaldisplayinit.cc

@@ -25,11 +25,13 @@
 
 #include <curses.h>
 #include <term.h>
+#include <stdlib.h>
+#include <string.h>
 
 using namespace Terminal;
 
 Display::Display( bool use_environment )
-  : has_ech( true ), has_bce( true ), posterize_colors( false )
+  : has_ech( true ), has_bce( true ), has_title( true ), posterize_colors( false )
 {
   if ( use_environment ) {
     int errret = -2;
@@ -70,6 +72,28 @@ Display::Display( bool use_environment )
       has_bce = false;
     }
 
+    /* Check if we can set the window title and icon name.  terminfo does not
+       have reliable information on this, so we hardcode a whitelist of
+       terminal type prefixes.  This is the list from Debian's default
+       screenrc, plus "screen" itself (which also covers tmux). */
+    static const char * const title_term_types[] = {
+      "xterm", "rxvt", "kterm", "Eterm", "screen"
+    };
+
+    has_title = false;
+    const char *term_type = getenv( "TERM" );
+    if ( term_type ) {
+      for ( size_t i = 0;
+            i < sizeof( title_term_types ) / sizeof( const char * );
+            i++ ) {
+        if ( 0 == strncmp( term_type, title_term_types[ i ],
+                           strlen( title_term_types[ i ] ) ) ) {
+          has_title = true;
+          break;
+        }
+      }
+    }
+
     /* posterization disabled because server now only advertises
        xterm-256color when client has colors = 256 */
     /*