mingw: try to figure out where TortoiseGit's (HANDLE)-2 comes from

It was reported that TortoiseGit passes in an stdin (HANDLE)-2 in
git-for-windows#1481 (comment).
Let's figure out where that comes from.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

compat/mingw.c

@@ -1655,6 +1655,9 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	memset(&si, 0, sizeof(si));
 	si.StartupInfo.cb = sizeof(si);
 	si.StartupInfo.hStdInput = winansi_get_osfhandle(fhin);
+	if (debug_1481)
+		warning("fhin: %d, hstdInput: %p",
+			fhin, si.StartupInfo.hStdInput);
 	si.StartupInfo.hStdOutput = winansi_get_osfhandle(fhout);
 	si.StartupInfo.hStdError = winansi_get_osfhandle(fherr);
 

compat/winansi.c

@@ -9,6 +9,8 @@
 #include "win32.h"
 #include "win32/lazyload.h"
 
+extern int debug_1481;
+
 static int fd_is_interactive[3] = { 0, 0, 0 };
 #define FD_CONSOLE 0x1
 #define FD_SWAPPED 0x2
@@ -660,6 +662,11 @@ void winansi_init(void)
  */
 HANDLE winansi_get_osfhandle(int fd)
 {
+	if (debug_1481)
+		warning("get_osf_handle for %d (fd_is_interactive %x %x): "
+			"%p (%p %p)",
+			fd, fd_is_interactive[1], fd_is_interactive[2],
+			(void *)_get_osfhandle(fd), hconsole1, hconsole2);
 	if (fd == 1 && (fd_is_interactive[1] & FD_SWAPPED))
 		return hconsole1;
 	if (fd == 2 && (fd_is_interactive[2] & FD_SWAPPED))