[Bug 46939] New: propvarutil.h: missing extern "C"

https://bugs.winehq.org/show_bug.cgi?id=46939

Bug ID: 46939
           Summary: propvarutil.h: missing extern "C"
           Product: Wine
           Version: unspecified
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

This header is a part of MinGW-W64 compiler.
When trying to #include <propvarutil.h> and use the 'PropVariantToInt64'
function, we get a linker error.

Looking for the latest master branch:
https://github.com/wine-mirror/wine/blob/master/include/propvarutil.h

Seems that there is no extern "C" around function prototypes.
Such workaround fixes the problem:

#include <shtypes.h>
#include <shlwapi.h>

#if defined(__cplusplus)
extern "C" {
#endif

#include <propvarutil.h>

#if defined(__cplusplus)
}
#endif

Fixes the problem