dropbear: add ssh-askpass support in configuration

binary size cost is much less than 1k.

tested on ath79/generic:
  bin: 215128 -> 215132 (+4b)
  ipk: 111183 -> 111494 (+311b)

Signed-off-by: Konstantin Demin <[email protected]>

package/network/services/dropbear/Config.in

@@ -99,4 +99,14 @@ config DROPBEAR_SCP
 	bool "Build dropbear with scp"
 	default y
 
+config DROPBEAR_ASKPASS
+	bool "Enable askpass helper support"
+	default n
+	depends on DROPBEAR_DBCLIENT
+	help
+		This enables support for ssh-askpass helper in dropbear client
+		in order to authenticate on remote hosts.
+
+		Increases binary size by about 0.1 kB (MIPS).
+
 endmenu

package/network/services/dropbear/Makefile

@@ -32,7 +32,7 @@ PKG_CONFIG_DEPENDS:= \
 	CONFIG_DROPBEAR_CURVE25519 CONFIG_DROPBEAR_ZLIB \
 	CONFIG_DROPBEAR_ED25519 CONFIG_DROPBEAR_CHACHA20POLY1305 \
 	CONFIG_DROPBEAR_UTMP CONFIG_DROPBEAR_PUTUTLINE \
-	CONFIG_DROPBEAR_DBCLIENT CONFIG_DROPBEAR_SCP
+	CONFIG_DROPBEAR_DBCLIENT CONFIG_DROPBEAR_SCP CONFIG_DROPBEAR_ASKPASS
 
 include $(INCLUDE_DIR)/package.mk
 
@@ -136,6 +136,7 @@ DB_OPT_CONFIG = \
 	DROPBEAR_ECDH|CONFIG_DROPBEAR_ECC|1|0 \
 	!!DROPBEAR_ECC_384|CONFIG_DROPBEAR_ECC_FULL|1|0 \
 	!!DROPBEAR_ECC_521|CONFIG_DROPBEAR_ECC_FULL|1|0 \
+	DROPBEAR_CLI_ASKPASS_HELPER|CONFIG_DROPBEAR_ASKPASS|1|0 \
 
 
 TARGET_CFLAGS += -DARGTYPE=3 -ffunction-sections -fdata-sections -flto