diff --git a/lib/connect.c b/lib/connect.c
index 0f7deb3cbab028ebbe0d0c1910ec8fee9970a636..5a376c34aaebd2eb6ad33e5f5c819eefd50ee489 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -921,7 +921,8 @@ void Curl_sndbufset(curl_socket_t sockfd)
   static int detectOsState = DETECT_OS_NONE;
 
   if(detectOsState == DETECT_OS_NONE) {
-#if (_WIN32_WINNT < _WIN32_WINNT_WIN2K)
+#if !defined(_WIN32_WINNT) || !defined(_WIN32_WINNT_WIN2K) || \
+    (_WIN32_WINNT < _WIN32_WINNT_WIN2K)
     OSVERSIONINFO osver;
 
     memset(&osver, 0, sizeof(osver));
diff --git a/lib/curl_sspi.c b/lib/curl_sspi.c
index 1cc18877f994534d16a20838865a251d6c92e0ec..bb41a879c73979de55615a5768dbe677a974f1ff 100644
--- a/lib/curl_sspi.c
+++ b/lib/curl_sspi.c
@@ -79,7 +79,8 @@ CURLcode Curl_sspi_global_init(void)
     DWORD majorVersion = 4;
     DWORD platformId = VER_PLATFORM_WIN32_NT;
 
-#if (_WIN32_WINNT < _WIN32_WINNT_WIN2K)
+#if !defined(_WIN32_WINNT) || !defined(_WIN32_WINNT_WIN2K) || \
+    (_WIN32_WINNT < _WIN32_WINNT_WIN2K)
     OSVERSIONINFO osver;
 
     memset(&osver, 0, sizeof(osver));