Recursive functions + bugfix for stack reallocation.

c/testdata

@@ -262,6 +262,12 @@ def id(x):x; 2000 as $x | def f(x):1 as $x | id([$x, x, x]); def g(x): 100 as $x
 999999999
 [[110.0, 130.0], [210.0, 130.0], [110.0, 230.0], [210.0, 230.0], [120.0, 160.0], [220.0, 160.0], [120.0, 260.0], [220.0, 260.0]]
 
+# test recursion
+def fac: if . == 1 then 1 else . * (. - 1 | fac) end; [.[] | fac]
+[1,2,3,4]
+[1,2,6,24]
+
+
 #
 # Assignment
 #