Merge branch 'mingw-isatty-and-dup2'

In December 2016 and January 2017, we revamped the Windows-specific
`isatty()` handling, replacing a hack by a more robust solution.

This patch is a follow-up we realized was necessary already in March
2017, but forgot to contribute to core Git yet.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

compat/mingw.h

@@ -417,6 +417,9 @@ int mingw_raise(int sig);
 int winansi_isatty(int fd);
 #define isatty winansi_isatty
 
+int winansi_dup2(int oldfd, int newfd);
+#define dup2 winansi_dup2
+
 void winansi_init(void);
 HANDLE winansi_get_osfhandle(int fd);
 

compat/winansi.c

@@ -474,6 +474,18 @@ static void die_lasterr(const char *fmt, ...)
 	va_end(params);
 }
 
+#undef dup2
+int winansi_dup2(int oldfd, int newfd)
+{
+	int ret = dup2(oldfd, newfd);
+
+	if (!ret && newfd >= 0 && newfd <= 2)
+		fd_is_interactive[newfd] = oldfd < 0 || oldfd > 2 ?
+			0 : fd_is_interactive[oldfd];
+
+	return ret;
+}
+
 static HANDLE duplicate_handle(HANDLE hnd)
 {
 	HANDLE hresult, hproc = GetCurrentProcess();