Fix handling of input files (e.g. with no newline at EOF) that could
make unifdef get into an unexpected state and call abort().

The new -B option compresses blank lines around a deleted section
so that blank lines around "paragraphs" of code don't get doubled.

The evaluator can now handle macros with arguments, and unbracketed
arguments to the "defined" operator.

Add myself to MAINTAINERS for unifdef.
Signed-off-by: Tony Finch <dot@dotat.at>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>