password utils: improve --help, make DEFAULT_PASSWD_ALGO visible if CHPASSWD

Was:
    $ cryptpw --help
    ...
    Print crypt(3) hashed PASSWORD

        -P,--password-fd=N	Read password from fd N
        -m,--method=TYPE	Encryption method
        -S,--salt=SALT

User: "What methods exist? which one os default?"

Now:
    Print crypt(3) hashed PASSWORD

        -P,--password-fd N	Read password from fd N
        -m,--method TYPE	des,md5,sha256/512 (default des)
        -S,--salt SALT

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/include/usage.src.h b/include/usage.src.h
index 78beccf..00369df 100644
--- a/include/usage.src.h
+++ b/include/usage.src.h
@@ -14,6 +14,14 @@
 
 #define NOUSAGE_STR "\b"
 
+#if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
+# define CRYPT_METHODS_HELP_STR "des,md5,sha256/512" \
+	" (default "CONFIG_FEATURE_DEFAULT_PASSWD_ALGO")"
+#else
+# define CRYPT_METHODS_HELP_STR "des,md5" \
+	" (default "CONFIG_FEATURE_DEFAULT_PASSWD_ALGO")"
+#endif
+
 INSERT
 
 #define busybox_notes_usage \
diff --git a/loginutils/chpasswd.c b/loginutils/chpasswd.c
index 2d268be..baafd35 100644
--- a/loginutils/chpasswd.c
+++ b/loginutils/chpasswd.c
@@ -13,9 +13,9 @@
 //config:	  and uses this information to update a group of existing users.
 //config:
 //config:config FEATURE_DEFAULT_PASSWD_ALGO
-//config:	string "Default password encryption method (passwd -a, cryptpw -m parameter)"
+//config:	string "Default encryption method (passwd -a, cryptpw -m, chpasswd -c ALG)"
 //config:	default "des"
-//config:	depends on PASSWD || CRYPTPW
+//config:	depends on PASSWD || CRYPTPW || CHPASSWD
 //config:	help
 //config:	  Possible choices are "d[es]", "m[d5]", "s[ha256]" or "sha512".
 
@@ -29,13 +29,13 @@
 //usage:       "Read user:password from stdin and update /etc/passwd\n"
 //usage:	IF_LONG_OPTS(
 //usage:     "\n	-e,--encrypted		Supplied passwords are in encrypted form"
-//usage:     "\n	-m,--md5		Use MD5 encryption instead of DES"
-//usage:     "\n	-c,--crypt-method	Use the specified method to encrypt the passwords"
+//usage:     "\n	-m,--md5		Eencrypt using md5, not des"
+//usage:     "\n	-c,--crypt-method ALG	"CRYPT_METHODS_HELP_STR
 //usage:	)
 //usage:	IF_NOT_LONG_OPTS(
 //usage:     "\n	-e	Supplied passwords are in encrypted form"
-//usage:     "\n	-m	Use MD5 encryption instead of DES"
-//usage:     "\n	-c	Use the specified method to encrypt the passwords"
+//usage:     "\n	-m	Eencrypt using md5, not des"
+//usage:     "\n	-c ALG	"CRYPT_METHODS_HELP_STR
 //usage:	)
 
 #include "libbb.h"
diff --git a/loginutils/cryptpw.c b/loginutils/cryptpw.c
index d630231..696e169 100644
--- a/loginutils/cryptpw.c
+++ b/loginutils/cryptpw.c
@@ -37,15 +37,15 @@
 //usage:#define cryptpw_full_usage "\n\n"
 //usage:       "Print crypt(3) hashed PASSWORD\n"
 //usage:	IF_LONG_OPTS(
-//usage:     "\n	-P,--password-fd=N	Read password from fd N"
+//usage:     "\n	-P,--password-fd N	Read password from fd N"
 /* //usage:  "\n	-s,--stdin		Use stdin; like -P0" */
-//usage:     "\n	-m,--method=TYPE	Encryption method"
-//usage:     "\n	-S,--salt=SALT"
+//usage:     "\n	-m,--method TYPE	"CRYPT_METHODS_HELP_STR
+//usage:     "\n	-S,--salt SALT"
 //usage:	)
 //usage:	IF_NOT_LONG_OPTS(
 //usage:     "\n	-P N	Read password from fd N"
 /* //usage:  "\n	-s	Use stdin; like -P0" */
-//usage:     "\n	-m TYPE	Encryption method TYPE"
+//usage:     "\n	-m TYPE	"CRYPT_METHODS_HELP_STR
 //usage:     "\n	-S SALT"
 //usage:	)
 
diff --git a/loginutils/passwd.c b/loginutils/passwd.c
index 52b66ca..b7b7423 100644
--- a/loginutils/passwd.c
+++ b/loginutils/passwd.c
@@ -32,7 +32,7 @@
 //usage:#define passwd_full_usage "\n\n"
 //usage:       "Change USER's password (default: current user)"
 //usage:     "\n"
-//usage:     "\n	-a ALG	Encryption method"
+//usage:     "\n	-a ALG	"CRYPT_METHODS_HELP_STR
 //usage:     "\n	-d	Set password to ''"
 //usage:     "\n	-l	Lock (disable) account"
 //usage:     "\n	-u	Unlock (enable) account"