mingw (git_terminal_prompt): turn on echo explictly

It turns out that when running in a Powershell window, we need to turn
on ENABLE_ECHO_INPUT because the default would be *not* to echo
anything.

This also ensures that we use the input mode where all input is read
until the user hits the Return key.

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

compat/terminal.c

@@ -77,17 +77,26 @@ static void restore_term(void)
 	hconin = INVALID_HANDLE_VALUE;
 }
 
-static int disable_echo(void)
+static int set_echo(int echo)
 {
-	hconin = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE,
-	    FILE_SHARE_READ, NULL, OPEN_EXISTING,
-	    FILE_ATTRIBUTE_NORMAL, NULL);
+	DWORD new_cmode;
+
+	if (hconin == INVALID_HANDLE_VALUE)
+		hconin = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE,
+				    FILE_SHARE_READ, NULL, OPEN_EXISTING,
+				    FILE_ATTRIBUTE_NORMAL, NULL);
 	if (hconin == INVALID_HANDLE_VALUE)
 		return -1;
 
 	GetConsoleMode(hconin, &cmode);
+	new_cmode = cmode | ENABLE_LINE_INPUT;
+	if (echo)
+		new_cmode |= ENABLE_ECHO_INPUT;
+	else
+		new_cmode &= ~ENABLE_ECHO_INPUT;
+
 	sigchain_push_common(restore_term_on_signal);
-	if (!SetConsoleMode(hconin, cmode & (~ENABLE_ECHO_INPUT))) {
+	if (!SetConsoleMode(hconin, new_cmode)) {
 		CloseHandle(hconin);
 		hconin = INVALID_HANDLE_VALUE;
 		return -1;
@@ -96,6 +105,11 @@ static int disable_echo(void)
 	return 0;
 }
 
+static int disable_echo(void)
+{
+	return set_echo(0);
+}
+
 static char *shell_prompt(const char *prompt, int echo)
 {
 	const char *read_input[] = {
@@ -169,6 +183,8 @@ char *git_terminal_prompt(const char *prompt, int echo)
 	if (result)
 		return result;
 
+	if (echo && set_echo(1))
+		return NULL;
 #endif
 
 	input_fh = fopen(INPUT_PATH, "r" FORCE_TEXT);