cat > 'Makefile.omk' <<EOF
default_CONFIG = CONFIG_DEBUG=y CONFIG_SLOW=n
default_CONFIG += CONFIG_NUM=123 CONFIG_ARCH=arm
default_CONFIG += CONFIG_QUOTES="Text+quotes"

SUBDIRS=subdir
EOF
cat > 'config.omk-correct' <<EOF
# Start of OMK config file
# This file should not be altered manually
# Overrides should be stored in file config.omk

# Config for subdir
CONFIG_SUBDIR=y
#CONFIG_DEBUG=x
# Config for 
CONFIG_DEBUG=y
CONFIG_SLOW=n
CONFIG_NUM=123
CONFIG_ARCH=arm
CONFIG_QUOTES="Text+quotes"
EOF
mkdir 'subdir'
echo 'default_CONFIG = CONFIG_SUBDIR=y CONFIG_DEBUG=x' > 'subdir/Makefile.omk'