arg: Use (void *)0 instead of NULL in error case of conditional expression

Even though NULL is a null pointer constant, the comma expression with
NULL at the end is not. So, we must ensure that either the type of the
comma expression is `char *` or `void *`, and we don't know this for NULL.

1 files changed, 1 insertions, 1 deletions

diff --git a/arg.h b/arg.h
index 8f93ee1..d428660 100644
--- a/arg.h
+++ b/arg.h
@@ -15,4 +15,4 @@
 	}
 
 #define EARGF(x) \
-	(done_ = 1, *++opt_ ? opt_ : argv[1] ? --argc, *++argv : ((x), abort(), NULL))
+	(done_ = 1, *++opt_ ? opt_ : argv[1] ? --argc, *++argv : ((x), abort(), (void *)0))