hush: fix environment and memory leaks, add tests for them
function old new delta
add_malloced_string_to_strings - 110 +110
run_list 1999 2086 +87
free_strings_and_unsetenv - 87 +87
hush_version_str - 18 +18
pseudo_exec_argv 139 146 +7
static.version_str 17 - -17
free_pipe 237 210 -27
done_word 790 642 -148
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 2/2 up/down: 309/-192) Total: 117 bytes
diff --git a/shell/hush_test/hush-vars/var_leaks.right b/shell/hush_test/hush-vars/var_leaks.right
new file mode 100644
index 0000000..d86bac9
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_leaks.right
@@ -0,0 +1 @@
+OK