Add freq_skip for use with rigs that do not have targetable VFO

Hopefully this allows them to work with gpredict.
However...setting frequency on TX/RX transition could take up to 1 second depending on gpredict polling rate.
https://github.com/Hamlib/Hamlib/issues/1493

doc/man1/rigctl.1

@@ -1429,6 +1429,13 @@ Can also use 1,2,3,4
 .EX
 Skips rig initialization -- useful when executing commands with rigctl to speed up things
 .
+.TP
+.BR freq_skip " " 'skip'
+.EX
+When skip!=0 skips setting freq on TX_VFO when in RX and on RX_VFO when in TX -- for use with gpredict and rigs that do not have TARGETABLE_VFO
+.
+.SH READLINE
+.
 .SH READLINE
 .
 If

include/hamlib/rig.h

@@ -2850,6 +2850,7 @@ struct rig_state {
     int dual_watch; /*!< Boolean DUAL_WATCH status */
     int post_ptt_delay;         /*!< delay after PTT to allow for relays and such */
     struct timespec freq_event_elapsed;
+    int freq_skip; /*!< allow frequency skip for gpredict RX/TX freq set */
 // New rig_state items go before this line ============================================
 };
 

src/conf.c

@@ -220,6 +220,11 @@ static const struct confparams frontend_cfg_params[] =
         "Multicast data UDP port for sending commands to rig",
         "4532", RIG_CONF_NUMERIC, { .n = { 0, 1000000, 1 } }
     },
+    {
+        TOK_FREQ_SKIP, "freq_skip", "Skip setting freq on non-active VFO",
+        "True enables skipping setting the TX_VFO when RX_VFO is receiving and skips RX_VFO when TX_VFO is transmitting",
+        "0", RIG_CONF_CHECKBUTTON, { }
+    },
 
     { RIG_CONF_END, NULL, }
 };
@@ -820,6 +825,15 @@ static int frontend_set_conf(RIG *rig, hamlib_token_t token, const char *val)
         rs->multicast_cmd_port = val_i;
         break;
 
+    case TOK_FREQ_SKIP:
+        if (1 != sscanf(val, "%ld", &val_i))
+        {
+            return -RIG_EINVAL;
+        }
+
+        rs->freq_skip = val_i != 0;
+        break;
+
     default:
         return -RIG_EINVAL;
     }

src/token.h

@@ -141,6 +141,8 @@
 #define TOK_MULTICAST_CMD_ADDR  TOKEN_FRONTEND(134)
 /** \brief rig: Multicast command server UDP port, default 4532 */
 #define TOK_MULTICAST_CMD_PORT  TOKEN_FRONTEND(135)
+/** \brief rig: Skip setting freq on opposite VFO when in split mode */
+#define TOK_FREQ_SKIP  TOKEN_FRONTEND(136)
 
 /*
  * rotator specific tokens