[RFC 8.3 0/3] Some style fixes

[Eli Zaretskii]

For the MinGW-specific problem with TUI colors, described here:

  https://www.sourceware.org/ml/gdb-patches/2019-03/msg00000.html
  https://www.sourceware.org/ml/gdb-patches/2019-03/msg00034.html

I propose to fix that as in the patch below.  Any objections to my
pushing this to the master and th gdb-8.3 branch (with suitable
ChangeLog entries)?

--- gdb/tui/tui-io.c~5	2019-03-12 09:18:11.713960000 +0200
+++ gdb/tui/tui-io.c	2019-03-13 09:09:15.185827600 +0200
@@ -37,6 +37,10 @@
 #include "cli-out.h"
 #include <fcntl.h>
 #include <signal.h>
+#ifdef __MINGW32__
+#include <windows.h>
+static SHORT ncurses_norm_attr;
+#endif
 #include "common/filestuff.h"
 #include "completer.h"
 #include "gdb_curses.h"
@@ -322,6 +326,16 @@ apply_ansi_escape (WINDOW *w, const char
       int fgi, bgi;
       if (get_color (fg, &fgi) && get_color (bg, &bgi))
 	{
+#ifdef __MINGW32__
+	  /* MS-Windows port of ncurses doesn't support implicit
+	     default foreground and background colors, so we must
+	     specify them explicitly when needed, using the colors we
+	     saw at startup.  */
+	  if (fgi == -1)
+	    fgi = ncurses_norm_attr & 15;
+	  if (bgi == -1)
+	    bgi = (ncurses_norm_attr >> 4) & 15;
+#endif
 	  int pair = get_color_pair (fgi, bgi);
 	  if (last_color_pair != -1)
 	    wattroff (w, COLOR_PAIR (last_color_pair));
@@ -803,6 +817,19 @@ tui_initialize_io (void)
 #else
   tui_rl_outstream = stdout;
 #endif
+
+#ifdef __MINGW32__
+  /* MS-Windows port of ncurses doesn't support default foreground and
+     background colors, so we must record the default colors at startup.  */
+  HANDLE hstdout = (HANDLE)_get_osfhandle (fileno (stdout));
+  DWORD cmode;
+  CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+  if (hstdout != INVALID_HANDLE_VALUE
+      && GetConsoleMode (hstdout, &cmode) != 0
+      && GetConsoleScreenBufferInfo (hstdout, &csbi))
+    ncurses_norm_attr = csbi.wAttributes;
+#endif
 }
 
 /* Get a character from the command window.  This is called from the