diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 6e9119d..d35d275 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -200,7 +200,7 @@ union semun {
 #define MDB_DEVEL 0
 #endif
 
-#if defined(WIN32) || (defined(EOWNERDEAD) && !defined(MDB_USE_SYSV_SEM))
+#if defined(_WIN32) || (defined(EOWNERDEAD) && !defined(MDB_USE_SYSV_SEM))
 #define MDB_ROBUST_SUPPORTED	1
 #endif
 
@@ -3881,7 +3881,7 @@ mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
 static int ESECT
 mdb_fsize(HANDLE fd, size_t *size)
 {
-#ifdef WIN32
+#ifdef _WIN32
 	LARGE_INTEGER fsize;
 
 	if (!GetFileSizeEx(fd, &fsize))
@@ -4047,7 +4047,7 @@ PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_
 extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;
 const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
 #pragma const_seg()
-#else	/* WIN32 */
+#else	/* _WIN32 */
 #pragma comment(linker, "/INCLUDE:__tls_used")
 #pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
 #pragma data_seg(".CRT$XLB")