Partially fixes SR-13831: Warnings while building on Linux.

[dhoepfl]

Fixed lstat warning by including <sys/stat.h>.

[MaxDesiatov]

Just curious what kind of warning are you referring to?

[dhoepfl]

Just curious what kind of warning are you referring to?

On systems that do not define statx, an fallback using lstat is used. The fallback implementation did not import sys/stat.h resulting in implicit declaration of function 'lstat' warnings whenever ForSwiftFoundationOnly.h was imported (I see it 160 times in a full build).

(See my bug report)

[spevans]

@swift-ci test

[spevans]

@dhoepfl Out of curiosity, what version of Linux are you compiling on?

[dhoepfl]

@dhoepfl Out of curiosity, what version of Linux are you compiling on?

Debian 10.6 (Buster)

% uname -a
Linux lightblue 4.19.0-10-amd64 #1 SMP Debian 4.19.132-1 (2020-07-24) x86_64 GNU/Linux

[dhoepfl]

I do not see why this test failed. It is not related to my change.

(Concurrent.cpp:78 should probably be ASSERT_GE because the reader might run twice before the writer was run again but that one did not trigger here.)

[spevans]

@swift-ci test

[dhoepfl]

Another unrelated fail.
Could you trigger another run, please?

(I do not know enough about the build system to understand why this test ever passed.)

[MaxDesiatov]

@swift-ci please test Linux platform

[spevans]

@dhoepfl I think the tests sometimes break because there is some code that is auto-merged into the llvm branches without being unit tested causing the unrelated failures.

[dhoepfl]

Thanks!