Fix check of _zip_filetime_to_time_t

lib/zip_source_file_win32.c

diff --git a/lib/zip_source_file_win32.c b/lib/zip_source_file_win32.c
index 0dea2c1..34645b7 100644
--- a/lib/zip_source_file_win32.c
+++ b/lib/zip_source_file_win32.c
@@ -184,7 +184,7 @@
         zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(GetLastError()));
         return false;
     }
-    if (_zip_filetime_to_time_t(mtimeft, &mtime) < 0) {
+    if (!_zip_filetime_to_time_t(mtimeft, &mtime)) {
         zip_error_set(&ctx->error, ZIP_ER_READ, ERANGE);
         return false;
     }