MSVC name mangling - c++

Question

I am trying to build Lua and QtLua with MSVC 2015 x86 and I have encountered an issue with exported/imported symbols.
Here is what I do forbuilding Lua 5.3.2 (source):
cl /MD /O2 /c /DLUA_BUILD_AS_DLL *.c
ren lua.obj lua.o
ren luac.obj luac.o
link /DLL /IMPLIB:lua5.3.2.lib /OUT:lua5.3.2.dll *.obj
link /OUT:lua.exe lua.o lua5.3.2.lib
lib /OUT:lua5.3.2-static.lib *.obj
link /OUT:luac.exe luac.o lua5.3.2-static.lib
So far it works and dependancy walker shows that functions are exported without any mangling.
Then I build QtLua using cmake and I'v got about 100 errors like:
error LNK2019: unresolved external symbol _lua_close referenced in function "public: virtual __thiscall QtLua::State::~State(void)" (??1State#QtLua##UAE#XZ)
So basically my issue is that the DLL exports lua_close and the linker looks for _lua_close.
After a bit of searching the _lua_close format seems legit as Microsoft documentation states that C symbols called with __cdecl are mangled with a '_' prefix.
However I don't get why the DLL exports unmangled names.
Function declaration when compiled in Lua (C files)
__declspec(dllexport) void (lua_close) (lua_State *L);
Function declaration when compiled in QtLua (C++ files)
extern "C" {
extern void (lua_close) (lua_State *L);
}

Answer 1

Quick answer
MSVC did not found the lua DLL (or lib).
Long answer
Exported C functions called using __cdecl are not mangled, whereas internal C functions called using __cdecl are mangled with a '_' prefix.
Source: http://wyw.dcweb.cn/stdcall.htm
To fix my issue I took all source files from QtLua and created a qmake project from them. And tadaa! It works! (Well, it doesn't because QtLua doesn't seem to be tested on anything else than gcc, but I got rid of this linker problem).
My conclusion is that:
MSVC complains about not finding _function and is in fact looking for function (or maybe both).
CMake, even if it found the lua library at config time, failed to pass the proper options to the linker at build time.