Replace missing getpass()

getpass() is traditional Unix, but has been withdrawn from POSIX.  As
such, it may be missing.  Check for that, and provide ersatz.  It's
not a real replacement, because it doesn't do the special magic
getpass() is supposed to do: read from /dev/tty without echo.

This bypasses our existing getpass() for Windows.  In contrast to the
portable getpass(), the Windows one tries to turn off echo, but that
doesn't work for me (MinGW & Wine).  Remove it.

src/client/login.c

@@ -44,6 +44,28 @@
 #include "misc.h"
 #include "proto.h"
 
+#ifndef HAVE_GETPASS
+#define getpass ersatz_getpass
+static char *
+ersatz_getpass(char *prompt)
+{
+    static char buf[128];
+    char *p;
+    size_t len;
+
+    printf("Note: your input is echoed to the screen\n");
+    printf("Your name? ");
+    fflush(stdout);
+    p = fgets(buf, sizeof(buf), stdin);
+    if (!p)
+	return NULL;
+    len = strlen(p);
+    if (p[len - 1] == '\n')
+	p[len - 1] = 0;
+    return p;
+}
+#endif
+
 int
 login(int s, char *uname, char *cname, char *cpass,
       int kill_proc, int utf8)