NetBSD's sed apparently does not understand the \+ syntax to match the preceeding
pattern one or more times. OTOH, {1,} seems to work, so use this syntax instead.
This caused the build to abort silently because make gives up on the targets that
depend on files in the "cmdline" directory.
LC_ALL=C gcc -MM -MG "$@" \
| sed -e "s@^\(.*\)\.o:@$object_dir/\1.d $object_dir/\1.o:@" \
- -e "s@[ ^]\([a-zA-Z0-9_]\+\.cmdline.h\)@ $cmdline_dir/\1@g"
+ -e "s@[ ^]\([a-zA-Z0-9_]\{1,\}\.cmdline.h\)@ $cmdline_dir/\1@g"