hush: partially fix wrong expansion on $IFS (bug 4027).

In the added testcase, before patch we failed 8 out of 9 tests,
now we fail only 2 (4th and 5th).

function                                             old     new   delta
expand_on_ifs                                        225     258     +33
expand_vars_to_list                                 1038    1054     +16
o_save_ptr_helper                                    115     119      +4
builtin_umask                                        132     133      +1
o_addQstr                                            165     161      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 54/-4)              Total: 50 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/shell/hush_test/hush-vars/var_expand_on_ifs.right b/shell/hush_test/hush-vars/var_expand_on_ifs.right
new file mode 100644
index 000000000..2ed2069f7
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_expand_on_ifs.right
@@ -0,0 +1,9 @@
+1 a b c
+2 a + b c
+3 a b c
+4 a  b c
+5 a  b c
+6 a b + c
+7 a b c
+8 a b  c
+9 a b  c
diff --git a/shell/hush_test/hush-vars/var_expand_on_ifs.tests b/shell/hush_test/hush-vars/var_expand_on_ifs.tests
new file mode 100755
index 000000000..a12ff8ec8
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_expand_on_ifs.tests
@@ -0,0 +1,11 @@
+b=' b '
+e=''
+echo 1 a $b c
+echo 2 a +$b c
+echo 3 a $e$b c
+echo 4 a "$e"$b c
+echo 5 a ""$b c
+echo 6 a $b+ c
+echo 7 a $b$e c
+echo 8 a $b"$e" c
+echo 9 a $b"" c