kconfig: Add default modules' symbols

boards/Kconfig

@@ -8,3 +8,10 @@ config BOARD
     string
     help
         Name of the currently selected board.
+
+config MOD_BOARD
+    bool
+    default y
+    depends on TEST_KCONFIG
+    help
+        Module which holds all board-specific files.

cpu/Kconfig

@@ -51,3 +51,10 @@ config CPU_ARCH
     string
     help
         Architecture of the currently selected CPU.
+
+config MOD_CPU
+    bool
+    default y
+    depends on TEST_KCONFIG
+    help
+        Module which holds all CPU-specific files.

drivers/periph_common/Kconfig

@@ -4,6 +4,13 @@
 # General Public License v2.1. See the file LICENSE in the top level
 # directory for more details.
 
+config MOD_PERIPH_INIT
+    bool "Peripherals auto-initialization"
+    default y
+    depends on TEST_KCONFIG
+    help
+        Auto-initialization of all used peripherals.
+
 menuconfig KCONFIG_MODULE_PERIPH_WDT
     bool "Configure Watchdog peripheral"
     depends on MODULE_PERIPH_WDT

sys/Kconfig

@@ -6,7 +6,15 @@
 #
 menu "System"
 
+rsource "auto_init/Kconfig"
 rsource "net/Kconfig"
 rsource "usb/Kconfig"
 
+config MOD_SYS
+    bool
+    default y
+    depends on TEST_KCONFIG
+    help
+        System module, it serves to pull in all the rest of system modules.
+
 endmenu # System

sys/auto_init/Kconfig

@@ -0,0 +1,15 @@
+# Copyright (c) 2020 HAW Hamburg
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+
+config MOD_AUTO_INIT
+    bool "Auto-initialization system"
+    default y
+    depends on TEST_KCONFIG
+    help
+        Auto-initialization module. Can be used to initialize modules (such as
+        drivers, or network interfaces) on start-up automatically. Disable if a
+        more custom initialization is required. If unsure, say Y.