diff --git a/libmaxsi/decl/ptrdiff_t.h b/libmaxsi/decl/ptrdiff_t.h
index bda0d3c8..0be69c72 100644
--- a/libmaxsi/decl/ptrdiff_t.h
+++ b/libmaxsi/decl/ptrdiff_t.h
@@ -1,4 +1,7 @@
 #ifndef _PTRDIFF_T_DECL
 #define _PTRDIFF_T_DECL
+#if !defined(_GCC_PTRDIFF_T)
+#define _GCC_PTRDIFF_T
 typedef __ptrdiff_t ptrdiff_t;
 #endif
+#endif
diff --git a/libmaxsi/decl/size_t.h b/libmaxsi/decl/size_t.h
index bead15ec..9a6246af 100644
--- a/libmaxsi/decl/size_t.h
+++ b/libmaxsi/decl/size_t.h
@@ -2,6 +2,9 @@
 #ifndef _SIZE_T_DECLARED /* Compabillity with gcc */
 #define _SIZE_T_DECL
 #define _SIZE_T_DECLARED
+#if !defined(_GCC_SIZE_T)
+#define _GCC_SIZE_T
 typedef __size_t size_t;
 #endif
 #endif
+#endif
diff --git a/libmaxsi/decl/wchar_t.h b/libmaxsi/decl/wchar_t.h
index abc0ffc4..bf5e1c64 100644
--- a/libmaxsi/decl/wchar_t.h
+++ b/libmaxsi/decl/wchar_t.h
@@ -1,6 +1,9 @@
 #ifndef _WCHAR_T_DECL
 #define _WCHAR_T_DECL
 #if !defined(__cplusplus)
+#if !defined(_GCC_WCHAR_T)
+#define _GCC_WCHAR_T
 typedef __wchar_t wchar_t;
 #endif
 #endif
+#endif