Compile mplayer's source code as dll in MinGW+MSYS environment

I try a way to compile mplayer as dll in MinGW+MSYS environment.
step 1, download source code of mplayer from http://www.mplayerhq.hu/design7/dload.html or download snapshot version http://www.mplayerhq.hu/MPlayer/releases/mplayer-export-snapshot.tar.bz2, I choice snapshot version. And uncompress it into C:\.

step 2, download MinGW+MSYS environment from http://sourceforge.net/projects/mplayer-ww/files, I download the latest version MinGW-full-20100518, and uncompress it into C:\MinGW.

step 3, create a file named autoconf, content listed below:
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./configure --disable-mencoder --disable-debug --enable-runtime-cpudetection --disable-sdl --disable-pthreads --enable-static --enable-w32threads
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step 4, modify c:\mplayer-export-2010-08-10\mplayer.c, find "#ifndef DISABLE_MAIN", add a line "#define DISABLE_MAIN" before it, save it.

step 5, create a file named Makefile_dll, content listed below:
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include config.mak


DIRS = input libaf libao2 libass libdvdcss libdvdnav libdvdnav/vm libdvdread4 libfaad2 libmpcodecs libmpdemux libmpeg2 libvo loader loader/dmo loader/dshow mp3lib osdep stream stream/freesdp stream/librtsp stream/realrtsp tremor vidix



ALL_OBJS = $(foreach DIR, $(DIRS), $(wildcard $(DIR)/*.o))

MPLAYER_OBJS = $(wildcard *.o)

INNER_LIBS = libavformat/libavformat.a libavcodec/libavcodec.a libavcore/libavcore.a libavutil/libavutil.a libpostproc/libpostproc.a libswscale/libswscale.a

# $(EXTRALIBS) come from config.mak
OTHER_LIBS = $(EXTRALIBS)

# $(EXTRALIBS_MPLAYER) come from config.mak
LIBS = $(EXTRALIBS_MPLAYER)

mplayer.dll : $(OBJS_MPLAYER) $(ALL_OBJS)
dllwrap --output-lib=libmplayer.a --dllname=$@ --driver-name=gcc --export-all-symbols $(MPLAYER_OBJS) $(ALL_OBJS) $(INNER_LIBS) $(OTHER_LIBS) $(LIBS)
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step 6, run C:\MinGW\msys.bat, do commands like below:
$cd /c/mplayer-export-2010-08-10
$./autoconf
$make
$make -f Makefile_dll

after follow those steps, you will get mplayer.dll and libmplayer.a two files under c:\mplayer-export-2010-08-10.

now, we can write test code in CodeBlocks and VS2008.
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#include
#include
#include

typedef int (*exp_lib_main)(int argc, char* argv[]);

int main(int argc, char* argv[])
{
// load library
HMODULE hModule = LoadLibrary("mplayer.dll");
if(!hModule)
return 0;

exp_lib_main _lib_main = (exp_lib_main)GetProcAddress(hModule, "lib_main");

char* prog_name = "mplayer";
char* file_name = "d:\\music\\01.mp3";

int _argc = 2;
char* _argv[] = {prog_name, file_name};
_lib_main(_argc, _argv);

FreeLibrary(hModule);
system("pause");
return 0;
}
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When I run code, executable target which compiled in CodeBlocks can run rightly, but in VS2008 is not right. why?