Re: head -r320458 (e.g.) amd64 -> powerpc (32-bit) cross-buildworld fails for time libc++ static_asserts and overflow/underflow of long long (system clang/clang++ 4 based build)

On 29 Jun 2017, at 12:04, Mark Millard <markmi_at_dsl-only.net> wrote:
> 
> [The libc++ code in question appears to not be ready for
> 32-bit contexts with 64 bit times. Disable
> experimental/filesystem for now? I've submitted
> llvm bugzilla 33638 for the issue and have
> added it to llvm's 25780, the FreeBSD META for
> clang.]

Yes, this also broke earlier on arm and mips, which is why there is the
following in lib/Makefile:

.if ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
_libcplusplus+= libc++experimental
.endif

I haven't yet found the time to address this issue.  Upstream should
already be aware of it, though.

One nasty problem with this is that it is not possible to figure out at
compile time what the size of time_t is.  You always need some sort of
configure-time test, and an external define.

-Dimitry