Clang 4.2 breakage, Node 5.2.0

[DomT4]

Hey Folks,

Had a report over at Homebrew of Node failing to build on OS X 10.7.5. It works built against GCC 5.x but fails against the system Clang, which is 4.2. As far as the README on the Node repo here states it should compile fine against that version of Clang.

I reproduced the failure on our testing infrastructure to check the reported error wasn't potentially user-related. Error is at the bottom of this gist but:

In file included from ../src/debug-agent.h:26:
../src/util-inl.h:206:14: error: use of undeclared identifier '__builtin_bswap16'
    dst[i] = __builtin_bswap16(src[i]);
             ^
In file included from ../test/cctest/util.cc:2:
../src/util-inl.h:206:14: error: use of undeclared identifier '__builtin_bswap16'
    dst[i] = __builtin_bswap16(src[i]);
             ^
In file included from ../src/fs_event_wrap.cc:2:

More or less that error reproduced through a bunch of files.

Just wanted to check whether or not the breakage is known and whether the Clang breakage for that version is an intentional thing.

[jbergstroem]

@DomT4 a big problem for us is that we have no 10.7 or 10.8 (or 10.9, 10.11) to test against in the ci cluster. As far as I know we intend to support 10.7, but since we don't test each commit its tricky to uphold.

[DomT4]

Can sympathise. We recently changed one of our Travis testing jobs (We use two CIs, Travis and Jenkins) to build using Ruby 1.8.x because we discovered pretty regularly we were merging code that because it was no longer being tested against older Ruby versions it'd break Homebrew on those platforms. It's a pain trying to cover every possible use case with CI.

I don't know if that sort of solution would be practical for you at all, using Travis to do commit testing on OS X 10.9 and 10.11 at least. As far as I know they don't offer anything older though, which still stumbles into this issue.

We can solve it on our end by enforcing usage of GCC-5 for the build on Lion, but thought the report upstream may be handy in some way.

[bnoordhuis]

#4290

[DomT4]

Thanks Ben! Appreciate the fix.