Audit bb_common_bufsiz usage, add script which looks for misuse.

tr: stop using globals needlessly.
code: -103 bytes

coreutils/split.c

@@ -49,7 +49,7 @@ static char *next_file(char *old, unsigned suffix_len)
 }
 
 #define read_buffer bb_common_bufsiz1
-enum { READ_BUFFER_SIZE = sizeof(bb_common_bufsiz1) - 1 };
+enum { READ_BUFFER_SIZE = COMMON_BUFSIZE - 1 };
 
 #define SPLIT_OPT_l (1<<0)
 #define SPLIT_OPT_b (1<<1)