u-boot/scripts/mkmakefile

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# Generates a small Makefile used in the root of the output
# directory, to allow make to be started from there.
# The Makefile also allow for more convinient build of external modules

# Usage
# $1 - Kernel src directory

# Only overwrite automatically generated Makefiles
# (so we do not overwrite kernel Makefile)
if test -e Makefile && ! grep -q Automatically Makefile
then
	exit 0
fi
if [ "${quiet}" != "silent_" ]; then
	echo "  GEN     Makefile"
fi

cat << EOF > Makefile
# Automatically generated by $0: don't edit

ifeq ("\$(origin V)", "command line")
VERBOSE := \$(V)
endif
ifneq (\$(VERBOSE),1)
Q := @
endif

MAKEFLAGS += --no-print-directory

.PHONY: __sub-make \$(MAKECMDGOALS)

__sub-make:
	\$(Q)\$(MAKE) -C $1 O=\$(CURDIR) \$(MAKECMDGOALS)

\$(filter-out __sub-make, \$(MAKECMDGOALS)): __sub-make
	@:
EOF