examples/gps: Allow GPS serial port to be specified as command line a…

…rgument, mark MINMEA dependency in Kconfig.

.gitignore

@@ -47,3 +47,4 @@ build
 .ccls-cache
 compile_commands.json
 .aider*
+.clang-format

examples/gps/Kconfig

@@ -7,6 +7,7 @@ config EXAMPLES_GPS
 	tristate "GPS example"
 	default n
 	select GPSUTILS_MINMEA_LIB
+    depends on GNSSUTILS_MINMEA_LIB
 	---help---
 		Enable the gps test example
 

examples/gps/gps_main.c

@@ -54,13 +54,22 @@ int main(int argc, FAR char *argv[])
   int cnt;
   char ch;
   char line[MINMEA_MAX_LENGTH];
+  char *ser_port = "/dev/ttyS1";
+
+  /* Get the GPS serial port argument. If none specified, default to ttyS1 */
+
+  if (argc > 1)
+    {
+      ser_port = argv[1];
+    }
 
   /* Open the GPS serial port */
 
-  fd = open("/dev/ttyS1", O_RDONLY);
+  fd = open(ser_port, O_RDONLY);
   if (fd < 0)
     {
-      printf("Unable to open file /dev/ttyS1\n");
+      fprintf(stderr, "Unable to open file %s\n", ser_port);
+      return 1;
     }
 
   /* Run forever */