diff --git a/arch/i386/bits/limits.h b/arch/i386/bits/limits.h
index f5778579..4e992453 100644
--- a/arch/i386/bits/limits.h
+++ b/arch/i386/bits/limits.h
@@ -22,11 +22,11 @@
 
 #define INT_MIN  (-1-0x7fffffff)
 #define INT_MAX  0x7fffffff
-#define UINT_MAX 0xffffffff
+#define UINT_MAX 0xffffffffU
 
 #define LONG_MIN  (-1-0x7fffffffL)
 #define LONG_MAX  0x7fffffffL
-#define ULONG_MAX 0xffffffffL
+#define ULONG_MAX 0xffffffffUL
 
 #define LLONG_MIN  (-1-0x7fffffffffffffffLL)
 #define LLONG_MAX  0x7fffffffffffffffLL
diff --git a/arch/x86_64/bits/limits.h b/arch/x86_64/bits/limits.h
index fadaf849..4f761b6c 100644
--- a/arch/x86_64/bits/limits.h
+++ b/arch/x86_64/bits/limits.h
@@ -20,11 +20,11 @@
 
 #define INT_MIN  (-1-0x7fffffff)
 #define INT_MAX  0x7fffffff
-#define UINT_MAX 0xffffffff
+#define UINT_MAX 0xffffffffU
 
 #define LONG_MIN  (-1-0x7fffffffffffffffL)
 #define LONG_MAX  0x7fffffffffffffffL
-#define ULONG_MAX 0xffffffffffffffffL
+#define ULONG_MAX 0xffffffffffffffffUL
 
 #define LLONG_MIN  (-1-0x7fffffffffffffffLL)
 #define LLONG_MAX  0x7fffffffffffffffLL
diff --git a/include/stdlib.h b/include/stdlib.h
index adacad85..047a5f3f 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -72,7 +72,7 @@ size_t wcstombs (char *, const wchar_t *, size_t);
 #define EXIT_FAILURE 1
 #define EXIT_SUCCESS 0
 
-#define MB_CUR_MAX 4
+#define MB_CUR_MAX ((size_t)+4)
 
 #define RAND_MAX (0x7fffffff)