cli: compare nmcli and NM versions

nmcli gets NM version and compares it with its own and complains
when they differ. This is to indicate that the results are not reliable,
because the API could differ. '--nocheck' switches the checks off.

cli/src/nmcli.h

@@ -49,7 +49,10 @@ typedef enum {
 	NMC_RESULT_ERROR_DEV_DISCONNECT = 6,
 
 	/* NetworkManager is not running */
-	NMC_RESULT_ERROR_NM_NOT_RUNNING = 7
+	NMC_RESULT_ERROR_NM_NOT_RUNNING = 7,
+
+	/* nmcli and NetworkManager versions mismatch */
+	NMC_RESULT_ERROR_VERSIONS_MISMATCH = 8
 } NMCResultCode;
 
 typedef enum {
@@ -107,6 +110,7 @@ typedef struct _NmCli {
 	char *required_fields;                            /* Required fields in output: '--fields' option */
 	NmcOutputField *allowed_fields;                   /* Array of allowed fields for particular commands */
 	NmcPrintFields print_fields;                      /* Structure with field indices to print */
+	gboolean nocheck_ver;                             /* Don't check nmcli and NM versions: option '--nocheck' */
 } NmCli;
 
 #endif /* NMC_NMCLI_H */