configs/microchip_sam9x60ek_mmc_dev_defconfig: add missing options

This defconfig needs wchar, thread debugging, and udev support to be
able to use all the packages it enables.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/1478738516

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/microchip_sam9x60ek_mmc_dev_defconfig

@@ -1,6 +1,10 @@
 BR2_arm=y
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_4=y
+BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
+BR2_PTHREAD_DEBUG=y
+BR2_TOOLCHAIN_BUILDROOT_CXX=y
 BR2_TARGET_GENERIC_HOSTNAME="sam9x60ek"
+BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
 BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
 BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/microchip/sam9x60ek_mmc/genimage.cfg"
 BR2_LINUX_KERNEL=y