Stop linking cmdline.c into the gtkapp-based programs.

They don't do normal command-line processing, so they don't need it. A
few stray references to machinery provided in there are now satisfied
instead by a new stub module nocmdline.c.

nocmdline.c

@@ -0,0 +1,42 @@
+/*
+ * nocmdline.c - stubs in applications which don't do the
+ * standard(ish) PuTTY tools' command-line parsing
+ */
+
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include "putty.h"
+
+/*
+ * Stub version of the function in cmdline.c which provides the
+ * password to SSH authentication by remembering it having been passed
+ * as a command-line option. If we're not doing normal command-line
+ * handling, then there is no such option, so that function always
+ * returns failure.
+ */
+int cmdline_get_passwd_input(prompts_t *p, const unsigned char *in, int inlen)
+{
+    return -1;
+}
+
+/*
+ * The main cmdline_process_param function is normally called from
+ * applications' main(). An application linking against this stub
+ * module shouldn't have a main() that calls it in the first place :-)
+ * but it is just occasionally called by other supporting functions,
+ * such as one in uxputty.c which sometimes handles a non-option
+ * argument by making up equivalent options and passing them back to
+ * this function. So we have to provide a link-time stub of this
+ * function, but it had better not end up being called at run time.
+ */
+int cmdline_process_param(const char *p, char *value,
+                          int need_save, Conf *conf)
+{
+    assert(FALSE && "cmdline_process_param should never be called");
+}
+
+/*
+ * This variable will be referred to, so it has to exist. It's ignored.
+ */
+int cmdline_tooltype = 0;