# Print error message to stderr and exit.  The error message can either be
# given as parameters or from stdin.
die()
{
	echo -n "fatal: " >/dev/stderr
	if [ "x$*" != x ]
	then
		echo $* >/dev/stderr
	else
		while read line;
		do
			echo $line >/dev/stderr
		done
	fi
	exit 1
}

# Parse an argument from an option in the form --option=argument.
parse_argument()
{
	echo $(echo $2 | sed -e "s/--$1=\\(.*\\)$/\\1/")
	return $?
}

# Insert all the escapes necessary to correctly quote a string for use in a
# shell command.
quote_string()
{
	for arg in "$@"
	do
		echo $1 | sed -e "s/'/\\'/g" \
					  -e 's/"/\\"/g' \
					  -e 's/|/\\|/g' \
					  -e 's/&/\\&/g' \
					  -e 's/;/\\;/g' \
					  -e 's/;/\\;/g' \
					  -e 's/(/\\(/g' \
					  -e 's/)/\\)/g' \
					  -e 's/</\\</g' \
					  -e 's/>/\\>/g' \
					  -e 's/ /\\ /g' \
					  -e "s/\t/\\\t/g" \
					  -e 's/\$/\\\$/g'
	done
}

# Add a definition to the compiler flags.  The optional second parameter is
# the unquoted value.
define()
{
	if test "x$2" = x
	then
		defines="$defines -D$1"
	else
		defines="$defines -D$1=$2"
	fi
}

# Add a definition to the compiler flags with a quoted value.
define_string()
{
	arg=$(quote_string "$2")
	define "$1" "\\\"$arg\\\""
}

undefine()
{
	for arg in "$@"
	do
		defines="$defines -U$arg"
	done
}

is_defined()
{
	for arg in "$@"
	do
		echo "$defines" | grep -e "-D$arg" 2>&1 >/dev/null || return 1
	done
	return 0
}

is_undefined()
{
	for arg in "$@"
	do
		echo "$defines" | grep -e "-U$arg" 2>&1 >/dev/null || return 1
	done
	return 0
}