Fix windows build

git-svn-id: file:///svn/toku/tokudb@20399 c7de825b-a66e-492c-adef-691d508d4ae1

windows/file.c

@@ -252,7 +252,7 @@ toku_os_full_pwrite (int fd, const void *org_buf, size_t len, toku_off_t off)
     assert(len == 0);
 }
 
-int
+ssize_t
 toku_os_pwrite (int fd, const void *org_buf, size_t len, toku_off_t off)
 {
     const uint8_t *buf = org_buf;