win32: changes to console mode handling

Add the environment variable BB_TERMINAL_MODE as a more general way
of controlling console/terminal mode setting.  The default remains
unchanged:  use virtual terminal mode for output if possible but
fall back to the console API with emulated ANSI escape sequences.

Currently valid settings are:

   0  Force use of console mode
   1  Force use of virtual terminal mode for output
   5  Prefer virtual terminal mode for output, fall back to console

Other values won't do anything useful until code elsewhere has been
updated.

BB_SKIP_ANSI_EMULATION remains available for backwards compatibility.
If both variables are set BB_TERMINAL_MODE takes precedence.

1 files changed, 5 insertions, 4 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 742067216..d78c6e828 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2340,9 +2340,9 @@ static void change_realtime(const char *) FAST_FUNC;
 
 #if ENABLE_PLATFORM_MINGW32
 static void FAST_FUNC
-change_skip_ansi(const char *newval UNUSED_PARAM)
+change_terminal_mode(const char *newval UNUSED_PARAM)
 {
-        skip_ansi_emulation(TRUE);
+        terminal_mode(TRUE);
 }
 
 # define LINENO_INDEX (5 + 2 * ENABLE_ASH_MAIL + ENABLE_ASH_GETOPTS)
@@ -2387,7 +2387,8 @@ static const struct {
         { VSTRFIXED|VTEXTFIXED|VUNSET, "HISTFILE"  , NULL            },
 #endif
 #if ENABLE_PLATFORM_MINGW32
-        { VSTRFIXED|VTEXTFIXED|VUNSET, BB_SKIP_ANSI_EMULATION, change_skip_ansi },
+        { VSTRFIXED|VTEXTFIXED|VUNSET, BB_SKIP_ANSI_EMULATION, change_terminal_mode },
+        { VSTRFIXED|VTEXTFIXED|VUNSET, BB_TERMINAL_MODE, change_terminal_mode },
 #endif
 };
 
@@ -14603,7 +14604,7 @@ cmdloop(int top)
                         inter++;
                         chkmail();
 #if ENABLE_PLATFORM_MINGW32
-                        skip_ansi_emulation(TRUE);
+                        terminal_mode(TRUE);
 #endif
                 }
                 n = parsecmd(inter);