Fix references to non-standard SIZE_T_MAX
Turns out C99 doesn't define SIZE_T_MAX, so let's not use it.
diff --git a/include/mbedtls/base64.h b/include/mbedtls/base64.h
index 18e8312..352c652 100644
--- a/include/mbedtls/base64.h
+++ b/include/mbedtls/base64.h
@@ -24,7 +24,6 @@
#define MBEDTLS_BASE64_H
#include <stddef.h>
-#include <limits.h>
#define MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL -0x002A /**< Output buffer too small. */
#define MBEDTLS_ERR_BASE64_INVALID_CHARACTER -0x002C /**< Invalid character in input. */
@@ -46,7 +45,8 @@
* *olen is always updated to reflect the amount
* of data that has (or would have) been written.
* If that length cannot be represented, then no data is
- * written to the buffer and *olen is set to SIZE_T_MAX.
+ * written to the buffer and *olen is set to the maximum
+ * length representable as a size_t.
*
* \note Call this function with dlen = 0 to obtain the
* required buffer size in *olen