Struct field function pointers, cstring, show toast error in cimport

tests/tnimterop_c.nim

@@ -21,6 +21,7 @@ var
   s2: STRUCT2
   s3: STRUCT3
   s4: STRUCT4
+  s5: STRUCT5
 
   e: ENUM
   e2: ENUM2 = enum5
@@ -33,6 +34,8 @@ var
   u: UNION1
   u2: UNION2
 
+  i: int
+
 pt = 3
 ct = 4
 
@@ -41,12 +44,18 @@ s2.field1 = 6
 s3.field1 = 7
 s4.field2[2] = 5
 s4.field3[3] = enum1
+s5.tci = test_call_int
+s5.tcp = test_call_param
+s5.tcp8 = test_call_param8
+check s5.tci() == 5
 
 e = enum1
 e2 = enum4
 
 u2.field2 = 'c'
 
+i = 5
+
 check test_call_int() == 5
 check test_call_param(5).field1 == 5
 check test_call_param2(5, s2).field1 == 11
@@ -56,6 +65,8 @@ check test_call_param5(5.0).field2 == 5.0
 check test_call_param6(u2) == 'c'
 u.field1 = 4
 check test_call_param7(u) == 4
+check test_call_param8(addr i) == 25.0
+check i == 25
 
 check e3 == enum7
 check e4 == enum11