opencv windows error

[ 26%] Building CXX object modules/highgui/CMakeFiles/opencv_highgui_pch_dephelp
.dir/opencv_highgui_pch_dephelp.cxx.obj
In file included from C:\Users\Acer\Downloads\opencv\bl\modules\highgui\opencv_h
ighgui_pch_dephelp.cxx:1:0:
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:2:7: erro
r: stray '#' in program
  +    #if !defined _WIN32_WINNT
       ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:3:11: err
or: stray '#' in program
  +        #ifdef HAVE_MSMF
           ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:4:15: err
or: stray '#' in program
  +            #define _WIN32_WINNT 0x0600 // Windows Vista
               ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:5:11: err
or: stray '#' in program
  +        #else
           ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:6:15: err
or: stray '#' in program
  +            #define _WIN32_WINNT 0x0500 // Windows 2000
               ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:7:11: err
or: stray '#' in program
  +        #endif
           ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:8:7: erro
r: stray '#' in program
  +    #endif
       ^
In file included from C:\Users\Acer\Downloads\opencv\bl\modules\highgui\opencv_h
ighgui_pch_dephelp.cxx:1:0:
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:1:0: erro
r: unterminated #if
  #if defined WIN32 || defined WINCE
 ^
C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src/precomp.hpp:2:2: erro
r: expected unqualified-id before '+' token
  +    #if !defined _WIN32_WINNT
  ^
In file included from c:\mingw\include\windows.h:47:0,
                 from C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src
/precomp.hpp:10,
                 from C:\Users\Acer\Downloads\opencv\bl\modules\highgui\opencv_h
ighgui_pch_dephelp.cxx:1:
c:\mingw\lib\gcc\mingw32\4.8.1\include\stdarg.h:98:9: error: '__gnuc_va_list' do
es not name a type
 typedef __gnuc_va_list va_list;
         ^
In file included from c:\mingw\include\windows.h:50:0,
                 from C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src
/precomp.hpp:10,
                 from C:\Users\Acer\Downloads\opencv\bl\modules\highgui\opencv_h
ighgui_pch_dephelp.cxx:1:
c:\mingw\include\winbase.h:1538:77: error: 'va_list' has not been declared
 WINBASEAPI DWORD WINAPI FormatMessageA(DWORD,PCVOID,DWORD,DWORD,LPSTR,DWORD,va_
list*);
                                                                             ^
c:\mingw\include\winbase.h:1539:78: error: 'va_list' has not been declared
 WINBASEAPI DWORD WINAPI FormatMessageW(DWORD,PCVOID,DWORD,DWORD,LPWSTR,DWORD,va
_list*);
                                                                              ^
In file included from c:\mingw\include\windows.h:55:0,
                 from C:/Users/Acer/Downloads/opencv/sources/modules/highgui/src
/precomp.hpp:10,
                 from C:\Users\Acer\Downloads\opencv\bl\modules\highgui\opencv_h
ighgui_pch_dephelp.cxx:1:
c:\mingw\include\winuser.h:4150:47: error: 'va_list' has not been declared
 WINUSERAPI int WINAPI wvsprintfA(LPSTR,LPCSTR,va_list arglist);
                                               ^
c:\mingw\include\winuser.h:4151:49: error: 'va_list' has not been declared
 WINUSERAPI int WINAPI wvsprintfW(LPWSTR,LPCWSTR,va_list arglist);
                                                 ^
modules\highgui\CMakeFiles\opencv_highgui_pch_dephelp.dir\build.make:67: recipe
for target 'modules/highgui/CMakeFiles/opencv_highgui_pch_dephelp.dir/opencv_hig
hgui_pch_dephelp.cxx.obj' failed
mingw32-make[2]: *** [modules/highgui/CMakeFiles/opencv_highgui_pch_dephelp.dir/
opencv_highgui_pch_dephelp.cxx.obj] Error 1
CMakeFiles\Makefile2:2039: recipe for target 'modules/highgui/CMakeFiles/opencv_
highgui_pch_dephelp.dir/all' failed
mingw32-make[1]: *** [modules/highgui/CMakeFiles/opencv_highgui_pch_dephelp.dir/
all] Error 2
Makefile:115: recipe for target 'all' failed
mingw32-make: *** [all] Error 2