sh: Fix some issues with CTL* bytes and ${var#pat}.

subevalvar() incorrectly assumed that CTLESC bytes were present iff the
expansion was quoted. However, they are present iff various processing such
as word splitting is to be done later on.

Example:
  v=@$e@$e@$e@
  y="${v##*"$e"}"
  echo "$y"
failed if $e contained the magic CTLESC byte.

Exp-run done by:	pav (with some other sh(1) changes)

1 files changed, 22 insertions, 0 deletions

diff --git a/tools/regression/bin/sh/expansion/trim6.0 b/tools/regression/bin/sh/expansion/trim6.0
new file mode 100644
index 0000000..3f753c4
--- /dev/null
+++ b/tools/regression/bin/sh/expansion/trim6.0
@@ -0,0 +1,22 @@
+# $FreeBSD$
+
+e=
+for i in 0 1 2 3; do
+	for j in 0 1 2 3 4 5 6 7; do
+		for k in 0 1 2 3 4 5 6 7; do
+			case $i$j$k in
+			000) continue ;;
+			esac
+			e="$e\\$i$j$k"
+		done
+	done
+done
+e=$(printf "$e")
+v=@$e@$e@
+y=${v##*"$e"}
+yq="${v##*"$e"}"
+[ "$y" = @ ] || echo "error when unquoted in non-splitting context"
+[ "$yq" = @ ] || echo "error when quoted in non-splitting context"
+[ "${v##*"$e"}" = @ ] || echo "error when quoted in splitting context"
+IFS=
+[ ${v##*"$e"} = @ ] || echo "error when unquoted in splitting context"