suppress loading of default config file for auto tests

Change-Id: I018de8dc31781756ef69738706531ad5f3dfb2af

README.md

@@ -267,6 +267,8 @@ The options are described in more detail below.
 	multiple times on the command line must be given only once in the config file, with the multiple
 	values separated by semicolons (see section *Interfaces configuration* below for an example).
 
+	As a special value, `none` can be passed here to suppress loading of the default config file.
+
 * --config-section
 
 	Specifies the *.ini* style section to be used in the config file. Multiple sections can be

lib/auxlib.c

@@ -129,6 +129,8 @@ void config_load(int *argc, char ***argv, GOptionEntry *app_entries, const char
 	use_config = default_config;
 	if (rtpe_common_config_ptr->config_file) {
 		use_config = rtpe_common_config_ptr->config_file;
+		if (!strcmp(use_config, "none"))
+			goto out;
 		fatal = 1;
 	}
 

t/auto-daemon-tests.pl

@@ -16,7 +16,8 @@ ok -x $ENV{RTPE_BIN}, 'RTPE_BIN points to executable';
 my $rtpe_stdout = File::Temp::tempfile() or die;
 my $rtpe_stderr = File::Temp::tempfile() or die;
 my $rtpe_pid = open3(undef, '>&'.fileno($rtpe_stdout), '>&'.fileno($rtpe_stderr),
-	$ENV{RTPE_BIN}, qw(-t -1 -i 203.0.113.1 -i 2001:db8:4321::1 -n 2223 -c 12345 -f -L 7 -E -u 2222));
+	$ENV{RTPE_BIN}, qw(--config-file=none -t -1 -i 203.0.113.1 -i 2001:db8:4321::1
+		-n 2223 -c 12345 -f -L 7 -E -u 2222));
 ok $rtpe_pid, 'daemon launched in background';
 
 # keep trying to connect to the control socket while daemon is starting up