Fix memory leak in typeset (rhbz#1036470)

A memory leak occurred when typeset was used in a function called
from within a command substitution. This fix was backported from
the 93v- beta by Red Hat on 22 Jan 2014. Source:
642af4d6/f/ksh-20120801-memlik3.patch

src/cmd/ksh93/include/name.h,
src/cmd/ksh93/sh/subshell.c:
- Replace the nv_subsaved() function by the version from ksh 93v-.
  This version frees a table from memory if the NV_TABLE flag is
  passed in the new second parameter, a bitmask for flags (which
  was oddly named 'table'; I've renamed it to 'flags').

src/cmd/ksh93/sh/name.c:
- nv_delete(): When calling nv_subsaved(), pass on the NV_TABLE
  flag if given.
- table_unset(): Call nv_delete() with the NV_TABLE flag.

src/cmd/ksh93/tests/leaks.sh:
- Add test based on the reproducer provided in Red Hat bug 1036470.

src/cmd/ksh93/tests/leaks.sh

@@ -228,5 +228,23 @@ err_exit_if_leak 'indexed array in function'
 
 LANG=$saveLANG		# comment out to test remaining leak (2/2)
 
+# ======
+# Memory leak in typeset (Red Hat #1036470)
+# Fix based on: https://src.fedoraproject.org/rpms/ksh/blob/642af4d6/f/ksh-20120801-memlik3.patch
+# The fix was backported from ksh 93v- beta.
+
+function myFunction
+{
+	typeset toPrint="something"
+	echo "${toPrint}"
+}
+state=$(myFunction)
+before=$(getmem)
+for ((i=0; i < N; i++))
+do	state=$(myFunction)
+done
+after=$(getmem)
+err_exit_if_leak 'typeset in function called by command substitution'
+
 # ======
 exit $((Errors<125?Errors:125))