coreutils: fix heap buffer overflow

This was introduced when improving UBsan reports. Probably a new variety
of bugs to be classified in the same family as silencing compiler and
coverity warnings. https://marc.info/?l=oss-security&m=170556990821840&w=2

ok bcallah (maintainer)

sysutils/coreutils/Makefile

@@ -2,6 +2,7 @@ COMMENT =		file, shell and text manipulation utilities
 
 DISTNAME =		coreutils-9.4
 CATEGORIES =		sysutils
+REVISION =		0
 
 MAINTAINER =		Brian Callahan <bcallah@openbsd.org>
 

sysutils/coreutils/patches/patch-src_split_c

@@ -0,0 +1,19 @@
+Fix heap buffer overflow
+
+https://github.com/coreutils/coreutils/commit/c4c5ed8f4e9cd55a12966d4f520e3a13101637d9
+https://marc.info/?l=oss-security&m=170556990821840&w=2
+
+Index: src/split.c
+--- src/split.c.orig
++++ src/split.c
+@@ -809,10 +809,7 @@ line_bytes_split (intmax_t n_bytes, char *buf, idx_t b
+             {
+               cwrite (n_out == 0, hold, n_hold);
+               n_out += n_hold;
+-              if (n_hold > bufsize)
+-                hold = xirealloc (hold, bufsize);
+               n_hold = 0;
+-              hold_size = bufsize;
+             }
+ 
+           /* Output to eol if present.  */