Define strnlen when it is not in libc

[Chi-Hua Chen via llvm-commits]

Duncan,

Attached is the one line change that removes && Data[Len - 1]. 'make
check' and 'make check-clang' from toplevel build directory succeed.

On Mon, Nov 28, 2016 at 7:06 PM, Chi-Hua Chen
<chc.w1005+clang1404 at gmail.com> wrote:
> Duncan,
>
>>> I have a question about the change in HeaderMap.cpp that introduced
>>> the first though: why is '&& Data[Len - 1]' necessary?
>>> https://github.com/llvm-mirror/clang/commit/839cd13b65d802f06276ff88d234419c38a44199#diff-860876c157b9f2ff75bce0d006cadc63
>>
>> Looks like it's unnecessary.  Do the tests pass without it?
>
> Yes, 'make check' still pass without it.
>
> - Chi-Hua
-------------- next part --------------
Index: clang/lib/Lex/HeaderMap.cpp
===================================================================
--- clang/lib/Lex/HeaderMap.cpp	(revision 288226)
+++ clang/lib/Lex/HeaderMap.cpp	(working copy)
@@ -158,7 +158,7 @@
   unsigned Len = strnlen(Data, MaxLen);
 
   // Check whether the buffer is null-terminated.
-  if (Len == MaxLen && Data[Len - 1])
+  if (Len == MaxLen)
     return None;
 
   return StringRef(Data, Len);