[VC++] error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

VC 6.0 에서는 잘 컴팔 되던것이..

1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(207) : error C2146: syntax error : missing ';' before identifier 'dbch_size'
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(207) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(207) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(208) : error C2146: syntax error : missing ';' before identifier 'dbch_devicetype'
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(208) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(208) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(209) : error C2146: syntax error : missing ';' before identifier 'dbch_reserved'
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(209) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(209) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\dbt.h(213) : error C2143: syntax error : missing ';' before '*'

간단한 해결방법은

/wd 4430

컴파일 옵션을 추가하면 해결.

그런데 헤더파일 잴 위에

#include <windows.h>

를 추가해도 해결되는군.. 왜 그런지는 모름.