udhcpc: kill undocumented -W, it was a no-op.

 fix option parsing in the case some CONFIG_x are off.
 disable -b on NOMMU, make backgrounding work correctly
 (if a bit differently from MMU case). Previously,
 it wasn't working at all.
 stop using global data for flags in main(), opt
 bitfield works as well.

function                                             old     new   delta
cryptpw_main                                         177     153     -24
packed_usage                                       24478   24452     -26
client_background                                     26       -     -26
udhcpc_main                                         2462    2372     -90
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/3 up/down: 0/-166)           Total: -166 bytes

1 files changed, 7 insertions, 12 deletions

diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h
index 97d3b3c9d..1ebccd405 100644
--- a/networking/udhcp/dhcpc.h
+++ b/networking/udhcp/dhcpc.h
@@ -9,14 +9,15 @@
 #endif
 
 struct client_config_t {
+        uint8_t arp[6];                 /* Our arp address */
         /* TODO: combine flag fields into single "unsigned opt" */
         /* (can be set directly to the result of getopt32) */
-        char foreground;                /* Do not fork */
-        char quit_after_lease;          /* Quit after obtaining lease */
-        char release_on_quit;           /* Perform release on quit */
-        char abort_if_no_lease;         /* Abort if no lease */
-        char background_if_no_lease;    /* Fork to background if no lease */
         char no_default_options;        /* Do not include default optins in request */
+#if ENABLE_FEATURE_UDHCP_PORT
+        uint16_t port;
+#endif
+        int ifindex;                    /* Index number of the interface to use */
+        uint8_t opt_mask[256 / 8];      /* Bitmask of options to send (-O option) */
         const char *interface;          /* The name of the interface to use */
         char *pidfile;                  /* Optionally store the process ID */
         const char *script;             /* User script to run at dhcp events */
@@ -24,16 +25,10 @@ struct client_config_t {
         uint8_t *vendorclass;           /* Optional vendor class-id to use */
         uint8_t *hostname;              /* Optional hostname to use */
         uint8_t *fqdn;                  /* Optional fully qualified domain name to use */
-        int ifindex;                    /* Index number of the interface to use */
-#if ENABLE_FEATURE_UDHCP_PORT
-        uint16_t port;
-#endif
-        uint8_t arp[6];                 /* Our arp address */
-        uint8_t opt_mask[256 / 8];      /* Bitmask of options to send (-O option) */
 };
 
 /* server_config sits in 1st half of bb_common_bufsiz1 */
-#define client_config (*(struct client_config_t*)(&bb_common_bufsiz1[COMMON_BUFSIZE/2]))
+#define client_config (*(struct client_config_t*)(&bb_common_bufsiz1[COMMON_BUFSIZE / 2]))
 
 #if ENABLE_FEATURE_UDHCP_PORT
 #define CLIENT_PORT (client_config.port)