Fix lua interpreter bug: the C call counter is already unwound by yield.

Decrementing it causes underflow and subsequent spurious stack overflow.

depends/lua/CMakeLists.txt

@@ -1,7 +1,7 @@
 PROJECT ( lua CXX )
 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
-SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-DLUA_USE_APICHECK")
+SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -DLUA_USE_APICHECK")
 
 IF(WIN32)
     ADD_DEFINITIONS(-D_CRT_SECURE_NO_DEPRECATE )

depends/lua/src/ldo.c

@@ -403,7 +403,7 @@ static void finishCcall (lua_State *L) {
   lua_assert(ci->u.c.k != NULL);  /* must have a continuation */
   lua_assert(L->nny == 0);
   /* finish 'luaD_call' */
-  L->nCcalls--;
+  //L->nCcalls--;
   /* finish 'lua_callk' */
   adjustresults(L, ci->nresults);
   /* call continuation function */
@@ -513,7 +513,7 @@ static void resume (lua_State *L, void *ud) {
         api_checknelems(L, n);
         firstArg = L->top - n;  /* yield results come from continuation */
       }
-      L->nCcalls--;  /* finish 'luaD_call' */
+      //L->nCcalls--;  /* finish 'luaD_call' */
       luaD_poscall(L, firstArg);  /* finish 'luaD_precall' */
     }
     unroll(L, NULL);