Cygwin: console: Add workaround for broken CSI3J in Win10 1809.

- In Win10 1809, the cursor position sometimes goes out of screen
  by clear command in console. This seems to be caused by escape
  sequence CSI3J (ESC[3J). This happens only for 1809. This patch
  is a workaround for the issue.

winsup/cygwin/fhandler_console.cc

@@ -1658,6 +1658,18 @@ bool fhandler_console::write_console (PWCHAR buf, DWORD len, DWORD& done)
   if (wincap.has_con_24bit_colors () && !con_is_legacy
       && memmem (buf, len*sizeof (WCHAR), L"\033[?1049", 7*sizeof (WCHAR)))
     need_fix_tab_position = true;
+  /* Workaround for broken CSI3J (ESC[3J) support in xterm compatible mode. */
+  if (wincap.has_con_24bit_colors () && !con_is_legacy &&
+      wincap.has_con_broken_csi3j ())
+    {
+      WCHAR *p = buf;
+      while ((p = (WCHAR *) memmem (p, (len - (p - buf))*sizeof (WCHAR),
+				    L"\033[3J", 4*sizeof (WCHAR))))
+	{
+	  memmove (p, p+4, (len - (p+4 - buf))*sizeof (WCHAR));
+	  len -= 4;
+	}
+    }
 
   if (con.iso_2022_G1
 	? con.vt100_graphics_mode_G1

winsup/cygwin/wincap.cc

@@ -42,6 +42,7 @@ wincaps wincap_vista __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:true,
     has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -69,6 +70,7 @@ wincaps wincap_7 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:true,
     has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -96,6 +98,7 @@ wincaps wincap_8 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -123,6 +126,7 @@ wincaps wincap_8_1 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -150,6 +154,7 @@ wincaps  wincap_10_1507 __attribute__((section (".cygwin_dll_common"), shared))
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -177,6 +182,7 @@ wincaps wincap_10_1703 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:true,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -204,6 +210,7 @@ wincaps wincap_10_1709 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:true,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -231,6 +238,7 @@ wincaps wincap_10_1803 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:true,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -258,6 +266,35 @@ wincaps wincap_10_1809 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_posix_rename_semantics:true,
     no_msv1_0_s4u_logon_in_wow64:false,
     has_con_24bit_colors:true,
+    has_con_broken_csi3j:true,
+  },
+};
+
+wincaps wincap_10_1903 __attribute__((section (".cygwin_dll_common"), shared)) = {
+  def_guard_pages:2,
+  mmap_storage_high:0x700000000000LL,
+  {
+    is_server:false,
+    needs_count_in_si_lpres2:false,
+    needs_query_information:false,
+    has_gaa_largeaddress_bug:false,
+    has_broken_alloc_console:true,
+    has_console_logon_sid:true,
+    has_precise_system_time:true,
+    has_microsoft_accounts:true,
+    has_processor_groups:true,
+    has_broken_prefetchvm:false,
+    has_new_pebteb_region:true,
+    has_broken_whoami:false,
+    has_unprivileged_createsymlink:true,
+    has_unbiased_interrupt_time:true,
+    has_precise_interrupt_time:true,
+    has_posix_unlink_semantics:true,
+    has_case_sensitive_dirs:true,
+    has_posix_rename_semantics:true,
+    no_msv1_0_s4u_logon_in_wow64:false,
+    has_con_24bit_colors:true,
+    has_con_broken_csi3j:false,
   },
 };
 
@@ -301,7 +338,9 @@ wincapc::init ()
 	break;
       case 10:
       default:
-	if (likely (version.dwBuildNumber >= 17763))
+	if (likely (version.dwBuildNumber >= 18362))
+	  caps = &wincap_10_1903;
+	else if (version.dwBuildNumber >= 17763)
 	  caps = &wincap_10_1809;
 	else if (version.dwBuildNumber >= 17134)
 	  caps = &wincap_10_1803;

winsup/cygwin/wincap.h

@@ -36,6 +36,7 @@ struct wincaps
     unsigned has_posix_rename_semantics		: 1;
     unsigned no_msv1_0_s4u_logon_in_wow64	: 1;
     unsigned has_con_24bit_colors		: 1;
+    unsigned has_con_broken_csi3j		: 1;
   };
 };
 
@@ -95,6 +96,7 @@ public:
   bool	IMPLEMENT (has_posix_rename_semantics)
   bool	IMPLEMENT (no_msv1_0_s4u_logon_in_wow64)
   bool	IMPLEMENT (has_con_24bit_colors)
+  bool	IMPLEMENT (has_con_broken_csi3j)
 
   void disable_case_sensitive_dirs ()
   {