fix compile warnings (bb#3882)

contrib/test/farm/farm.c

@@ -105,7 +105,7 @@ static void
 dir(const char *dirname)
 {
 	int i, nmachines;
-	const struct dirent *dirent;
+	struct dirent *dirent;
 	struct machine *m;
 	DIR *d = opendir(dirname);
 	char **results;

libclamav/mbox.c

@@ -2897,7 +2897,7 @@ rfc1341(message *m, const char *dir)
 			time(&now);
 			for(n = 1; n <= t; n++) {
 				char filename[NAME_MAX + 1];
-				const struct dirent *dent;
+				struct dirent *dent;
 #if defined(HAVE_READDIR_R_3) || defined(HAVE_READDIR_R_2)
 				union {
 					struct dirent d;

libclamav/readdb.c

@@ -2698,7 +2698,7 @@ const char *cl_retdbdir(void)
 int cl_statinidir(const char *dirname, struct cl_stat *dbstat)
 {
 	DIR *dd;
-	const struct dirent *dent;
+	struct dirent *dent;
 #if defined(HAVE_READDIR_R_3) || defined(HAVE_READDIR_R_2)
 	union {
 	    struct dirent d;