make define2mk.sed work on FreeBSD

In the thread "[1.3.2-rc1] MPC8548CDS/MPC8555CDS configs fails to link",
the define2mk.sed script was identified as the source of the link
failure on FreeBSD. The problem is that sed(1) does not always support
the '+' operator. It isn't on FreeBSD. The attach patch implements the
equivalent, using the '*' operator instead and should work everywhere.

Signed-off-by: Marcel Moolenaar <marcelm@juniper.net>

tools/scripts/define2mk.sed

@@ -7,11 +7,11 @@
 #
 
 # Only process values prefixed with #define CONFIG_
-/^#define CONFIG_[A-Za-z0-9_]\+/ {
+/^#define CONFIG_[A-Za-z0-9_][A-Za-z0-9_]*/ {
 	# Strip the #define prefix
 	s/#define *//;
 	# Change to form CONFIG_*=VALUE
-	s/ \+/=/;
+	s/  */=/;
 	# Drop trailing spaces
 	s/ *$//;
 	# drop quotes around string values