Merge yet another fixup

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

compat/mingw.h

@@ -472,6 +472,7 @@ extern int (*win32_is_mount_point)(struct strbuf *path);
 #define PATH_SEP ';'
 char *mingw_query_user_email(void);
 #define query_user_email mingw_query_user_email
+struct strbuf;
 char *mingw_strbuf_realpath(struct strbuf *resolved, const char *path);
 #define platform_strbuf_realpath mingw_strbuf_realpath
 #if !defined(__MINGW64_VERSION_MAJOR) && (!defined(_MSC_VER) || _MSC_VER < 1800)