options: Complete the transition to numeric toggles (`#if') For the sake of review, this commit alters only the code; the affiliated comments within the source files also need to be updated, but doing so now would obscure the operational changes that have been made here. * All on/off options have been switched to the numeric `#if' variant; that is the only way to make this `default_options.h.in' thing work in a reasonable manner. * There is now some very minor compile-time checking of the user's choice of options. * NO_FAST_EXPTMOD doesn't seem to be used, so it has been removed. * ENABLE_USER_ALGO_LIST was supposed to be renamed DROPBEAR_USER_ALGO_LIST, and this commit completes that work. * DROPBEAR_FUZZ seems to be a relatively new, as-yet undocumented option, which was added by the following commit: commit 6e0b539e9ca0b5628c6c5a3d118ad6a2e79e8039 Author: Matt Johnston <[email protected]> Date: Tue May 23 22:29:21 2017 +0800 split out checkpubkey_line() separately It has now been added to `sysoptions.h' and defined as `0' by default. * The configuration option `DROPBEAR_PASSWORD_ENV' is no longer listed in `default_options.h.in'; it is no longer meant to be set by the user, and is instead left to be defined in `sysoptions.h' (where it was already being defined) as merely the name of the environment variable in question: DROPBEAR_PASSWORD To enable or disable use of that environment variable, the user must now toggle `DROPBEAR_USE_DROPBEAR_PASSWORD'. * The sFTP support is now toggled by setting `DROPBEAR_SFTPSERVER', and the path of the sFTP server program is set independently through the usual SFTPSERVER_PATH.

--- a/cli-auth.c	Wed Feb 14 23:09:40 2018 +0800
+++ b/cli-auth.c	Thu Jul 20 19:38:26 2017 +0000
@@ -60,9 +60,11 @@
 	*/
 	if (ses.keys->trans.algo_comp != DROPBEAR_COMP_ZLIB_DELAY) {
 		ses.authstate.authtypes = AUTH_TYPE_PUBKEY;
+#if DROPBEAR_USE_DROPBEAR_PASSWORD
 		if (getenv(DROPBEAR_PASSWORD_ENV)) {
 			ses.authstate.authtypes |= AUTH_TYPE_PASSWORD | AUTH_TYPE_INTERACT;
 		}
+#endif
 		if (cli_auth_try() == DROPBEAR_SUCCESS) {
 			TRACE(("skipped initial none auth query"))
 			/* Note that there will be two auth responses in-flight */
@@ -335,7 +337,7 @@
 {
 	char* password = NULL;
 	
-#ifdef DROPBEAR_PASSWORD_ENV
+#if DROPBEAR_USE_DROPBEAR_PASSWORD
 	/* Password provided in an environment var */
 	password = getenv(DROPBEAR_PASSWORD_ENV);
 	if (password)