[BUILTIN] Honor tab as IFS whitespace when splitting fields in readcmd

When I try to split fields by tabs, dash doesn't honour multiple tabs
between fields as whitespace (at least that's how I interpret [1],
please correct me if I'm wrong).

#!/bin/sh

# "1\t2\t\t3"
TESTSTRING="1	2		3"

# only "\t"
IFS="	"
echo "$TESTSTRING" | while read p1 p2 p3; do
	echo "p1=${p1}, p2=${p2}, p3=${p3}"
done

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/expand.h b/src/expand.h
index 1862aea..405af0b 100644
--- a/src/expand.h
+++ b/src/expand.h
@@ -67,6 +67,9 @@ void expari(int);
 #define rmescapes(p) _rmescapes((p), 0)
 char *_rmescapes(char *, int);
 int casematch(union node *, char *);
+void recordregion(int, int, int);
+void removerecordregions(int); 
+void ifsbreakup(char *, struct arglist *);
 
 /* From arith.y */
 intmax_t arith(const char *);