make more tests green for C++; refs #7870

tests/ccgbugs/tcvarargs.nim

@@ -12,6 +12,7 @@ discard """
 
 {.emit: """
 #include <stdarg.h>
+#include <stdio.h>
 
 void foo(int n, ...) {
   NI64 k;

tests/ccgbugs/tinefficient_const_table.nim

@@ -6,9 +6,9 @@ of
 words'''
   cmd: r"nim c --hints:on $options -d:release $file"
   ccodecheck: "! @'genericSeqAssign'"
+  target: "c"
 """
 
-
 # bug #4354
 import tables
 import sets

tests/ccgbugs/tmissingbracket.nim

@@ -38,7 +38,7 @@ type
         t:int
     SubObject* = object of TestObj
 
-method test*(t:var TestObj) =
+method test*(t:var TestObj) {.base.} =
     echo "test called"
 
 method test*(t:var SubObject) =

tests/ccgbugs/tmissingvolatile.nim

@@ -2,6 +2,7 @@ discard """
   output: "1"
   cmd: r"nim c --hints:on $options -d:release $file"
   ccodecheck: "'NI volatile state;'"
+  target: "C"
 """
 
 # bug #1539