configure: Include objbase.h when checking for CoTaskMemFree

ddc1cd5cdd defined WIN32_LEAN_AND_MEAN
globally, which makes for much fewer transitive includes from
windows.h. With that define, CoTaskMemFree no longer gets
implicitly declared by just including windows.h, but one has to
include the right header objbase.h too.

That commit caused ole32 to no longer get detected, which caused
dxva2 to no longer be enabled. This gets fixed by this patch.

Signed-off-by: Martin Storsjö <martin@martin.st>

configure

@@ -6488,7 +6488,7 @@ done
 check_lib advapi32 "windows.h"            RegCloseKey          -ladvapi32
 check_lib bcrypt   "windows.h bcrypt.h"   BCryptGenRandom      -lbcrypt &&
     check_cpp_condition bcrypt bcrypt.h "defined BCRYPT_RNG_ALGORITHM"
-check_lib ole32    "windows.h"            CoTaskMemFree        -lole32
+check_lib ole32    "windows.h objbase.h"  CoTaskMemFree        -lole32
 check_lib shell32  "windows.h shellapi.h" CommandLineToArgvW   -lshell32
 check_lib psapi    "windows.h psapi.h"    GetProcessMemoryInfo -lpsapi