Suppress some "variable might be clobbered by longjmp" warnings.

Seen with an older gcc version.  I'm not sure these represent any real
risk factor, but still a bit scary.  Anyway we have lots of other
volatile-marked variables in this code, so a couple more won't hurt.

src/pl/plperl/Util.xs

@@ -37,7 +37,7 @@ static void
 do_util_elog(int level, SV *msg)
 {
 	MemoryContext oldcontext = CurrentMemoryContext;
-	char *cmsg = NULL;
+	char	   * volatile cmsg = NULL;
 
 	PG_TRY();
 	{
@@ -67,6 +67,7 @@ static text *
 sv2text(SV *sv)
 {
 	char	   *str = sv2cstr(sv);
+
 	return cstring_to_text(str);
 }
 

src/pl/plpython/plpython.c

@@ -1516,7 +1516,7 @@ static PLyProcedure *
 PLy_procedure_get(Oid fn_oid, bool is_trigger)
 {
 	HeapTuple	procTup;
-	PLyProcedureEntry *entry;
+	PLyProcedureEntry * volatile entry;
 	bool		found;
 
 	procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(fn_oid));
@@ -3234,7 +3234,7 @@ PLy_spi_prepare(PyObject *self, PyObject *args)
 	void	   *tmpplan;
 	volatile MemoryContext oldcontext;
 	volatile ResourceOwner oldowner;
-	int			nargs;
+	volatile int nargs;
 
 	if (!PyArg_ParseTuple(args, "s|O", &query, &list))
 		return NULL;
@@ -3470,7 +3470,7 @@ PLy_spi_execute_plan(PyObject *ob, PyObject *list, long limit)
 
 	PG_TRY();
 	{
-		char	   *nulls;
+		char  * volatile nulls;
 		volatile int j;
 
 		if (nargs > 0)